Method for navigation and positioning of receiver and receiver

ABSTRACT

The present application provides a method for navigation and positioning of a receiver, including: receiving basic broadcast messages and correction parameters of a plurality of satellites, and establishing a pseudorange observation equation and a carrier-phase observation equation corresponding to each of satellites respectively; correcting the pseudorange observation equation and the carrier-phase observation equation using the received correction parameters to obtain the corrected pseudorange observation equation and the corrected carrier-phase observation equation; constructing a first observation according to the corrected pseudorange observation equation and the corrected carrier-phase observation equation; constructing a second observation according to the corrected pseudorange observation equation and the corrected carrier-phase observation equation; and jointly solving the obtained first observations and second observations of the plurality of satellites to obtain anoperation result of user positioning.

TECHNICAL FIELD OF THE DISCLOSURE

The present application relates to the field of navigation andpositioning, and in particular to a method for navigation andpositioning of a receiver, a receiver and a computer readable medium.

BACKGROUND

At present, the Global Navigation Satellite System (GNSS) is becomingmore and more popular, the application of GNSS systems and the use ofGNSS receivers are becoming more and more widespread. In an actualpractice, there is at least a problem that the accuracy of positioningof a GNSS receiver is not high enough and that the convergence thereofis slow.

SUMMARY

In view of this, the technical schemes proposed by the presentapplication are described in detail below.

In one aspect, the present application provides a method for navigationand positioning of a receiver, the method comprising: receiving basicbroadcast messages and correction parameters of a plurality ofsatellites, and establishing a pseudorange observation equation and acarrier-carrier-phase observation equation corresponding to each ofsatellites respectively based on the received basic broadcast messages;correcting the pseudorange observation equation and the carrier-phaseobservation equation using the received correction parameterscorresponding to each of satellites to obtain the corrected pseudorangeobservation equation and the corrected carrier-phase observationequation; constructing an ionosphere-free combined observation of eachof satellites as a first observation according to the correctedpseudorange observation equation and the corrected carrier-phaseobservation equation; constructing a second observation corresponding toeach of satellites according to the corrected pseudorange observationequation and the corrected carrier-phase observation equation; andjointly solving the obtained first observations and second observationsof the plurality of satellites to obtain an operation result of userpositioning, wherein the correction parameters is selected from thefollowing combinations: a partition comprehensive correctionx₄; and acombination of the partition comprehensive correctionx₄ and at least oneof an orbit correctionx₁, a clock difference correctionx₂ and anionosphere correctionx₃.

In some embodiments, the method can be applied to a single-frequency,dual-frequency or tri-frequency receiver.

In another aspect, the present application provides a receiver,comprising: an antenna for receiving basic broadcast messages andcorrection parameters; at least one storage apparatus for storing thebasic broadcast messages and the correction parameters received; aprocessing module for processing the basic broadcast messages andcorrection parameters in the storage apparatus to obtain an operationresult of user positioning; and a user interaction module for indicatingthe result of the user positioning, wherein the processing module isused to perform the following operations: receiving basic broadcastmessages and correction parameters of a plurality of satellites, andestablishing a pseudorange observation equation and a carrier-phaseobservation equation corresponding to each of satellites respectivelybased on the received basic broadcast messages; correcting thepseudorange observation equation and the carrier-phase observationequation using the received correction parameters corresponding to eachof satellites to obtain the corrected pseudorange observation equationand the corrected carrier-phase observation equation; constructing anionosphere-free combined observation of each of satellites as a firstobservation according to the corrected pseudorange observation equationand the corrected carrier-phase observation equation; constructing asecond observation corresponding to each of satellites according to thecorrected pseudorange observation equation and the correctedcarrier-phase observation equation; and jointly solving the obtainedfirst observations and second observations of the plurality ofsatellites to obtain the operation result of the user positioning,wherein the correction parameters is selected from the followingcombinations: a partition comprehensive correction x₄; and a combinationof the partition comprehensive correction x₄ and at least one of anorbitcorrection x₁, a clock difference correction x₂ and an ionospherecorrection x₃.

In a further aspect of the present application, the present applicationprovides a non-transitory computer readable medium comprisinginstructions which, when executed by at least one processing module,cause the at least one processing module to perform a method fornavigational and positioning, the method comprising: receiving basicbroadcast messages and correction parameters of a plurality ofsatellites, and establishing a pseudorange observation equation and acarrier-phase observation equation corresponding to each of satellitesrespectively based on the received basic broadcast messages; correctingthe pseudorange observation equation and the carrier-phase observationequation using the received correction parameters corresponding to eachof satellites to obtain the corrected pseudorange observation equationand the corrected carrier-phase observation equation; constructing anionosphere-free combined observation of each of satellites as a firstobservation according to the corrected pseudorange observation equationand the corrected carrier-phase observation equation; constructing asecond observation corresponding to each of satellites according to thecorrected pseudorange observation equation and the correctedcarrier-phase observation equation; and jointly solving the obtainedfirst observations and second observations of the plurality ofsatellites to obtain the operation result of the user positioning,wherein the correction parameters is selected from the followingcombinations: a partition comprehensive correction x₄; and a combinationof the partition comprehensive correction x₄ and at least one of anorbitcorrection x₁, a clock difference correction x₂ and an ionospherecorrection x₃.

Embodiments of the present invention have at least one of the followingbeneficial effects.

The embodiments of the present invention, by receiving and using thecorrection parameters, refine the error correction in the positioningand improve the accuracy of positioning of the receiver (achieve atleast the decimeter-level accuracy of positioning), thereby meeting therequirements of high-accuracy positioning of different industriesincluding, but not limited to, measurement, mechanical control,precision agriculture, intelligent transportation, logistics and assettracking, engineering management, engineering construction, blindnavigation, early warning monitoring, emergency rescue, etc.Furthermore, the embodiments of the invention further improve theconvergence speed, are able to converge quickly and shorten theinitialization time of the receiver, so that the receiver is quicklybrought into a substantial high-accuracy positioning working state.

Other aspects and embodiments of the present application will becomeapparent from the following detailed description, and the principles ofthe present application are explained by way of example in conjunctionwith the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly explain the technical schemes of theembodiments of the present invention, the attached drawings of theembodiments will be briefly introduced below. Obviously, the attacheddrawings in the following description merely relate to some embodimentsof the present invention, they do not limit the present invention.

FIG. 1 shows a satellite positioning system according to an embodimentof the present invention;

FIG. 1A schematically shows the structure of a correction parametersinformation generating apparatus 100;

FIG. 2 schematically shows the flow of superimposing a correctionparameters with a basic navigation message protocol;

FIG. 3A is a timing matching schematic diagram of superimposing an orbitcorrection and a partition comprehensive correction on the basis of abasic navigation message;

FIG. 3B is a timing matching schematic diagram of superimposing a clockdifference correction and a partition comprehensive correction on thebasis of a basic navigation message;

FIG. 3C is another timing matching schematic diagram of superimposing aclock difference correction and a partition comprehensive correction onthe basis of a basic navigation message;

FIG. 3D is a timing matching schematic diagram of superimposing an orbitcorrection, a clock difference correction and a partition comprehensivecorrection on the basis of a basic navigation message;

FIG. 3E is another timing matching schematic diagram of superimposing anorbit correction, a clock difference correction and a partitioncomprehensive correction on the basis of a basic navigation message;

FIG. 4 shows a block diagram of the configuration of main units of amessage broadcast apparatus for an enhanced parameter in a satellitenavigation system according to an embodiment of the present invention;

FIG. 5 is a schematic diagram illustrating a navigation message framestructure model according to an embodiment of the present invention;

FIG. 6 is a schematic diagram illustrating navigation messageinformation contents in a navigation message frame structure modelaccording to an embodiment of the present invention;

FIG. 7 is a schematic diagram illustrating an arrangement relationshipin time of pages of a sub-frame in a navigation message frame structuremodel according to an embodiment of the present invention;

FIGS. 8A-1 to 8L-2 are schematic diagrams respectively illustratingexamples of message arrangements of pages 1˜6 of sub-frames 2˜4 forbroadcasting partition comprehensive correction parameters according toan embodiment of the present invention;

FIGS. 9A-1 to 9B-3 are schematic diagrams respectively illustratingexamples of message arrangements of pages 5˜6 of sub-frame 3 forbroadcasting satellite clock difference correction parameters accordingto an embodiment of the present invention;

FIGS. 10A-1 to 10E-2 are schematic diagrams respectively illustratingexamples of message arrangements of pages 23˜30, 83˜90 of sub-frame 5for broadcasting GPS partition comprehensive correction parametersaccording to an embodiment of the present invention;

FIGS. 11A-1 to 11E-2 are schematic diagrams respectively illustratingexamples of message arrangements of pages 117˜120, 31, 91 of sub-frame 5for broadcasting satellite orbit correction parameters according to anembodiment of the present invention;

FIG. 12 is a flowchart illustrating a message broadcast method for anenhanced parameter in a satellite navigation system according to anotherembodiment of the present invention;

FIG. 13 shows a schematic structural block diagram of a receiver systemaccording to an embodiment of the present application;

FIG. 14 shows a flowchart of a navigation and positioning method of asingle-frequency receiver using correction parameters including apartition comprehensive correction x4, an orbit correction x₁, a clockdifference correction x₂ and an ionosphere correction x₃ according toanother embodiment of the present application;

FIG. 15 shows a flowchart of a dual-frequency navigation and positioningmethod of a dual-frequency receiver using correction parametersincluding a partition comprehensive correction x₄, an orbit correctionx₁, a clock difference correction x₂ and an ionosphere correction x₃according to another embodiment of the present application;

FIG. 16 shows a flowchart of a navigation and positioning method of asingle-frequency receiver using correction parameters including apartition comprehensive correction x₄, a clock difference correction x₂and an ionosphere correction x₃ according to another embodiment of thepresent application;

FIG. 17 shows a flowchart of a navigation and positioning method of adual-frequency receiver using correction parameters including apartition comprehensive correction x₄, a clock difference correction x₂and an ionosphere correction x₃ according to another embodiment of thepresent application;

FIG. 18 shows a flowchart of a navigation and positioning method of atri-frequency receiver using correction parameters including a partitioncomprehensive correction x₄, an orbit correction x₁, a clock differencecorrection x₂ and an ionosphere correction x₃ according to anotherembodiment of the present application;

FIG. 19 shows a flowchart of a navigation and positioning method of atri-frequency receiver using correction parameters including a partitioncomprehensive correction x₄, a clock difference correction x₂ and anionosphere correction x₃ according to another embodiment of the presentapplication;

FIG. 20 shows a flowchart of a navigation and positioning method of atri-frequency receiver using correction parameters including a partitioncomprehensive correction x₄, an orbit correction x₁, a clock differencecorrection x₂ and an ionosphere correction x₃ according to anotherembodiment of the present application;

FIG. 21 shows a flowchart of a navigation and positioning method of atri-frequency receiver using correction parameters including a partitioncomprehensive correction x₄, a clock difference correction x₂ and anionosphere correction x₃ according to another embodiment of the presentapplication;

FIG. 22 shows a flowchart of a navigation and positioning method of asingle-frequency receiver using correction parameters including apartition comprehensive correction x₄ according to another embodiment ofthe present application;

FIG. 23 shows a flowchart of a navigation and positioning method of adual-frequency receiver using correction parameters including apartition comprehensive correction x₄ according to another embodiment ofthe present application;

FIG. 24 shows a flowchart of a navigation and positioning method of atri-frequency receiver using correction parameters including a partitioncomprehensive correction x₄ according to another embodiment of thepresent application;

FIG. 25 shows a flowchart of a navigation and positioning method of atri-frequency receiver using correction parameters including a partitioncomprehensive correction x₄ according to another embodiment of thepresent application.

In the following specification, a drawing that is split across multiplesheets is denoted with “-1”, “-2”, and so on. For example, FIG. 8A issplit across three sheets that are labeled as 8A-1, 8A-2, and 8A-3. Forease of explanation, any drawing that is split across multiple sheetsmay be referred to by its common label. For instance, the sheets labeledas FIGS. 8A-1, 8A-2, and 8A-3 are referred to collectively as FIG. 8A,the sheets labeled as FIGS. 8B-1, 8B-2, and 8B-3 are referred tocollectively as FIG. 8B, and so on. Further, reference is made toattached drawings that form a part thereof and in which it is shown byway of setting forth specific exemplary embodiments in which thedisclosure is practiced. These embodiments are described in sufficientdetail to enable those skilled in the art to practice the conceptsdisclosed herein, and it should be understood that modifications tovarious embodiments disclosed may be made and other embodiments may beused without departing from the scope of the present disclosure.Therefore, the following detailed description shall not to be consideredas with a limiting implication.

DETAILED DESCRIPTION

In order to make the objectives, technical schemes and advantages ofembodiments of the present invention clearer, the technical schemes ofthe embodiments of the present invention will be described clearly andcompletely in conjunction with the attached drawings of the embodimentsof the present invention in the following. Obviously, the describedembodiments are a part of the embodiments of the present invention, notall of the embodiments. All other embodiments obtained by those ordinaryskills in the art based on the described embodiments of the presentinvention without creative efforts are within the scope of protection ofthe present invention.

Unless otherwise defined, technical terms or scientific terms usedherein should be of general meanings as understood by those ordinaryskills in the art to which the present invention belongs. The terms“first”, “second” and the like, as used in the specification and claimsof the present invention patent application, do not denote any order,quantity or importance, but rather are used to distinguish betweendifferent components. Similarly, “a” or “an” or the like does not mean aquantitative limitation but means that at least one exists.

A navigation satellite usually broadcasts only basic navigation messageto meet the user's requirement for 10-meter-level basic navigation andpositioning. In order to improve the accuracy of positioning, thecorrection parameters are usually supplied to the user terminal(receiver) via a communication satellite or through a network. That isto say, the user terminal (receiver) employs the received basicnavigation message and correction parameters to determine its ownposition, so that the accuracy of positioning can be improved. However,the accuracy of positioning in the prior art can only reach meter-level,still cannot meet the requirements for accuracy of positioning ofcertain industries, for example, industries such as precisionagriculture, high-accuracy measurement and the like, which requireachieving decimeter-level accuracy of positioning to meet the needs ofdaily work.

The aforementioned correction parameters can also be broadcast throughan independent satellite navigation enhancement system. For example, thecurrent navigation enhancement systems mainly include the WAAS (WideArea Augmentation System) system in the United States, the EGNOS(European Geostationary Navigation Overlay Service) system in Europe,the MSAS (Multi-functional Satellite Augmentation System) in Japan, andthe SDCM (Differential Corrections and Monitoring) system in Russia,etc. These systems are operational control systems independent of GPS orGLONASS.

Correction parameters is for the purpose of improving the accuracy ofthe system's real-time service, the basic idea is to distinguish betweenthe main error sources such as satellite orbit error, satellite clockdifference and ionosphere delay, establish a model of each error source,and generate corrections for correcting the errors of these parameters(clock difference, orbit, etc.) in the basic navigation. The calculatedcorrections are referred to as correction parameters (or enhancedparameters, enhanced corrections, enhancement information), thecorrection parameters are broadcast to the user terminal (user end,receiver) via a satellite communication link or through a network.

In view of this, according to a satellite positioning method and asatellite positioning system of an embodiment of the present invention,by designing a high-accuracy wide-area differential parameter model,correction parameters are broadcast in a satellite navigation message,and a method of protocol superimposition is employed to achieve theintegrated design of the basic navigation message plus correctionparameters, for example, the correction parameters are broadcast on thebasis of the basic navigation message, the correction parameters includethe orbit correction, the satellite clock difference correction, theionosphere correction and the partition comprehensive correction, etc.and the superimposed fusion matching of the correction parameters can berealized, then the correction parameters are directly broadcastuniformly by the navigation satellite of the satellite navigationsystem. Through the wide-area difference model, an integrated servicebased on the basic navigation, navigation enhancement and precisionpositioning of the satellite navigation system itself can be realized,and wide-area navigation and positioning of the decimeter-level accuracycan be realized without adding other communication channels.

In addition, existing navigation systems, such as GPS, have a basicnavigation message structure employing a fixed frame structure, and thescalability thereof is poor; and the basic navigation information andcorrection parameters are not uniformly broadcast, but are broadcastseparately by two systems, a satellite navigation system and a satellitenavigation enhancement system (e.g., GPS and WAAS), resource consumptionis large, the link resource occupation is large, not the combination offast and slow, and the flexibility is low.

According to the satellite positioning method and the satellitepositioning system of the embodiment of the present invention, it isalso possible to realize the message arrangement and the messagebroadcasting for various error corrections (for example, clockdifference correction, orbit correction, partition comprehensivecorrection, etc.) in the satellite navigation system. For example, inaccordance with the byte sizes and the update frequencies of respectiveparameters involved in the error correction that needs to be broadcast,their respective insertion positions (page positions of a sub-frame) inthe reserved space in the original navigation message frame structuremodel (including the basic navigation information) is determined toperform the message arrangement, and a ground station uploads thearranged message via an uplink injection link to a satellite forbroadcasting.

According to the satellite positioning method and the satellitepositioning system of the embodiment of the present invention, it isfurther possible to provide a method for navigation and positioning of areceiver, a receiver and a computer readable medium. According to thetype of parameters received by the receiver and the specific conditionsof the receiver, the receiver can provide matching strategies ofdifferent algorithms to properly process the received parameters tocorrect the obtained observation values of pseudoranges andcarrier-phases, thereby realizing the positioning calculation whichimproves accuracy.

FIG. 1 shows a satellite positioning system according to an embodimentof the present invention. As shown in FIG. 1, the satellite positioningsystem includes navigation satellites, a base station, an observationstation, and may also include a receiver.

The observation station includes a monitoring terminal and a correctionparameters information generating apparatus. The monitoring terminalreceives the observation data transmitted from the navigationsatellites, and the correction parameters information generatingapparatus generates correction parameters based on the receivedobservation data, then these correction parameters are transmitted bythe monitoring terminal to the base station. For example, the correctionparameters information generating apparatus first performspreprocessing, precise orbit determination and time synchronizationprocessing on the satellite observation data, then calculates one ormore of the following parameters: the ionosphere correction, thereal-time clock difference correction, the real-time orbit correction,the partition comprehensive correction, etc. according to specificrequirements.

The correction parameters generated by the correction parametersinformation generating apparatus at the observation station aretransmitted by the observation station monitoring terminal to the basestation.

A switch and an apparatus for superimposing, encoding, and broadcastingof message parameters are provided at the base station. The switchreceives the basic navigation message from the satellites, the apparatusfor superimposing, encoding and broadcasting of message parametersencodes the correction parameters for enhancement into the basicnavigation message through protocol superimposition to realize theintegration of the message, and set the broadcasting. For example, theapparatus for superimposing, encoding and broadcasting of messageparameters may also set the broadcast frequencies of the correctionparameters, select the link for the message broadcasting, set thebroadcast format and the broadcast strategy of the message, verify themessage broadcast performance, and transmit the data message to beinjected to the satellite in the uplink to the switch. The switch of thesatellite base station transmits the integrated-coded message to thesatellite via the uplink injection link, with the satellite being asatellite (i.e., a navigation satellite) for providing navigation andpositioning which may belong to different satellite navigation systems,for example, may be a GPS satellite, a Beidou satellite, or the like.

The navigation satellite broadcasts the integrated satellite navigationmessage, that it receives from the base station, in which the correctionparameters is added, and it can be received by the receiver. Thereceiver includes a receiving-end message processing apparatus whichdecodes the integrated satellite navigation message received by thereceiver, decodes correction parameters for enhancement therefrom, andconstructs observations, performs parameter correction (embodiments ofthe present invention have no limitation on the order of constructingobservations and performing parameter correction), the positioningsolution, etc., to obtain the positioning information based on thecorrection parameters, and may also perform the accuracy evaluation.

Next, the above-described signal and data processing proceduresperformed at the observation station, the base station and the receiverare separately described.

As described above, there is provided at the observation station acorrection parameters information generating apparatus which maygenerate correction parameters such as an ionosphere correction, areal-time clock difference correction, a real-time orbit correction, anda partition comprehensive correction, to enhance the satellitenavigation (positioning) accuracy, then multiple parameters therein aresuperimposed at the base station.

In order to achieve the superimposition of the correction parameters, amodel of a correction parameters is first established and a correctionparameters is generated based on the model.

According to the satellite positioning method and the satellitepositioning system of the embodiment of the present invention, not onlythe correction parameters can be realized through being broadcast onlyby a navigation satellite, but the correction parameters may also bebroadcast through a ground-based network.

The satellite orbit in the basic navigation message generally needs tobe forecasted for 1˜2 hours, and its forecast error will increase overtime. The satellite orbit correction parameters is to make use of theobservation data of the ground observation station network and resolvethe error of the satellite orbit forecast in real time so as to correctthe satellite orbit in the basic navigation message in real time, it mayinclude satellite identifiers, satellite orbit corrections and theequivalent distance error status identifiers of the satellite orbitcorrections.

For example, for orbit corrections, a model may be established asfollows:

Orbit corrections of n Beidou satellites and m GPS satellites at time t0may be expressed as:

${dORB}_{t_{0}} = \begin{bmatrix}{dx}_{1}^{BDS} & {dy}_{1}^{BDS} & {dz}_{1}^{BDS} & {d{\overset{.}{x}}_{1}^{BDS}} & {d{\overset{.}{y}}_{1}^{BDS}} & {d{\overset{.}{z}}_{1}^{BDS}} \\{dx}_{2}^{BDS} & {dy}_{2}^{BDS} & {dz}_{2}^{BDS} & {d{\overset{.}{x}}_{2}^{BDS}} & {d{\overset{.}{y}}_{2}^{BDS}} & {d{\overset{.}{z}}_{2}^{BDS}} \\\vdots & \vdots & \vdots & \vdots & \vdots & \vdots \\{dx}_{n}^{BDS} & {dy}_{n}^{BDS} & {dz}_{n}^{BDS} & {d{\overset{.}{x}}_{n}^{BDS}} & {d{\overset{.}{y}}_{n}^{BDS}} & {d{\overset{.}{y}}_{n}^{BDS}} \\{dx}_{1}^{GPS} & {dy}_{1}^{GPS} & {dz}_{1}^{GPS} & {d{\overset{.}{x}}_{1}^{GPS}} & {d{\overset{.}{y}}_{1}^{GPS}} & {d{\overset{.}{z}}_{1}^{GPS}} \\{dx}_{2}^{GPS} & {dy}_{2}^{GPS} & {dz}_{2}^{GPS} & {d{\overset{.}{x}}_{2}^{GPS}} & {d{\overset{.}{y}}_{2}^{GPS}} & {d{\overset{.}{z}}_{2}^{GPS}} \\\vdots & \vdots & \vdots & \vdots & \vdots & \vdots \\{dx}_{m}^{GPS} & {dy}_{m}^{GPS} & {dz}_{m}^{GPS} & {d{\overset{.}{x}}_{m}^{GPS}} & {d{\overset{.}{y}}_{m}^{GPS}} & {d{\overset{.}{z}}_{m}^{GPS}}\end{bmatrix}_{t_{0}}$

In the above equation, dx, dy, dz d{dot over (x)}, d{dot over (y)}, dżeach represents the corrections and the rates of change of thethree-dimensional vector value XYZ of the satellite orbit correction,and the superscript indicates whether the satellite is a GPS or BDSsatellite, the subscript is a satellite number.

From time t0 to time ti, within the effective time of the satelliteorbit correction, the satellite orbit corrections dx, dy, dz may becalculated by the following equation:

$\begin{bmatrix}{dx} \\{dy} \\{dz}\end{bmatrix}_{ti} = {\begin{bmatrix}{dx} \\{dy} \\{dz}\end{bmatrix}_{t\; 0} + {\left( {{ti} - {t\; 0}} \right) \cdot \begin{bmatrix}{d\overset{.}{x}} \\{d\overset{.}{y}} \\{d\overset{.}{z}}\end{bmatrix}_{t\; 0}}}$

Through the above-mentioned orbit correction model, the satellite orbitcorrection may be calculated by using different methods. By accuratelycorrecting spatial signals, satellite orbit corrections represent anorbit normal error correction, an orbit radial error correction and anorbit tangential error correction in different viewing directions. Forexample, the satellite orbit correction (correction value) may becomprehensively resolved by using a pseudorange observation value and acarrier-phase observation value.

As mentioned before, the satellite clock difference in the basicnavigation message generally needs to be forecasted for 1˜2 hours, itsforecast error will increase over time. The satellite clock differencecorrection is to make use of the observation data of the groundobservation station network and resolve the error of the satellite clockdifference forecast in real time so as to correct the satellite clockdifference parameters in the basic navigation message in real time, itmay include satellite identifiers, satellite clock differencecorrections, the satellite clock difference correction truncation errorsand the satellite differential equivalent distance error statusidentifiers.

For example, for a clock difference correction, a model may beestablished as follows:

Clock difference corrections of n Beidou satellites and m GPS satellitesat time t0 may be expressed as:dt _(t) ₀ =[dt ₁ ^(BDS) dt ₂ ^(BDS) ⋅ ⋅ ⋅ dt _(n) ^(BDS) dt ₁ ^(GPS) dt₂ ^(GPS) ⋅ ⋅ ⋅ dt _(m) ^(GPS)]_(t) ₀

From time t0 to time ti, within the effective time of the satelliteclock difference correction, the satellite clock difference correctiondt may be calculated by the following equation:dt _(ti) =dt _(t)0The satellite clock difference correction dt_(ti) indicates thecomprehensive influence of the satellite ephemeris error and thesatellite star clock error on the user distance error for the i-thsatellite, and is used to correct the comprehensive error of thesatellite ephemeris and the satellite clock difference in the navigationmessage. In addition, the satellite clock difference correction residuedt_(resi) may be further calculated and used. The satellite clockdifference correction residue represents the part of the i-th satellitestar clock difference correction that below 0.1 m, and is used tocorrect the error of the satellite clock difference correction below 0.1m, thereby the performance of the parameters is further improved andspatial signals are accurately corrected.

The basic navigation message provides model parameters for ionospheredelay correction, but it is a function that fits the measured resultsinto 8 or 14 parameters, resulting in the loss of accuracy, andgenerally its update frequency is low and the forecast time is long. Theionosphere correction is suitable for the correction of the real-timeionosphere delay.

For example, for an ionosphere correction, a model dI may be establishedas follows:

${dI}_{t_{0}} = \begin{bmatrix}I_{1}^{1} & I_{2}^{1} & \cdots & I_{\ln}^{1} \\I_{1}^{2} & I_{2}^{2} & \cdots & I_{\ln}^{2} \\\vdots & \vdots & \ddots & \vdots \\I_{1}^{bn} & I_{2}^{bn} & \cdots & I_{\ln}^{bn}\end{bmatrix}_{t_{0}}$

wherein, I_(ln) ^(bn) is the vertical ionosphere delay on the piercegrid and is divided into [1, ln] intervals in the longitude directionand [1, bn] intervals in the latitude direction according to the definedarea. From time t0 to time ti, within the effective time of theionosphere correction, the ionosphere correction is a function of theionosphere delay with the latitude and the longitude of the pierce pointbeing b and l respectively. Further, the ionosphere delay function withthe latitude and the longitude of the pierce point being (b,l) can beregarded as the bilinear difference of ionosphere delays off ouradjacent grid points.

The environment segment area comprehensive correction is mainly used tocorrect the orbit clock difference residual error and the commonresidual error of the space environment segment error in the area.

The partition comprehensive correction parameters according to theembodiment of the present invention is further improved on the basis ofthe environment segment area comprehensive correction parameters(including troposphere and space segment compensation). Due to thehigh-accuracy orbit correction, clock difference correction andionosphere correction, and correction of the troposphere empiricalmodel, the rest of the error is relatively stable. Therefore, thepartition setting is added, that is, partition is performed according tothe observation areas, one correction is designed per area (region) andper satellite, so as to form a partition comprehensive correctionparameters model to further improve the effect of the error improvement.

For example, the design of the partition comprehensive correction isbased on the assumption that within a certain distance, the errors ofthe user (receiver) on the satellite side and the propagation path arerelevant. Therefore, the observation area may be divided into multiplepartitions (regions), the partition comprehensive correction is obtainedby integrating the first result calculated in real time using theobservation data from observation stations in each partition with thefirst result from observation stations in one partition, and isbroadcast to the user in real time, thus realizing real-timehigh-accuracy positioning of the navigation user. The first result mayinclude a carrier-phase observation residual.

For example, for a partition comprehensive correction, a model dΦ may beestablished as follows:

${d\;\Phi_{t_{0}}} = \left\lbrack \begin{matrix}{d\;\Phi_{1,1}^{BDS}} & {d\;\Phi_{1,2}^{BDS}} & \cdots & {d\;\Phi_{l,n}^{BDS}} & {d\;\Phi_{1,1}^{GPS}} & {d\;\Phi_{1,2}^{GPS}} & \cdots & {d\;\Phi_{l,m}^{GPS}} \\{d\;\Phi_{2,1}^{BDS}} & {d\;\Phi_{2,2}^{BDS}} & \cdots & {d\;\Phi_{2,n}^{BDS}} & {d\;\Phi_{2,1}^{GPS}} & {d\;\Phi_{2,2}^{GPS}} & \cdots & {d\;\Phi_{2,m}^{GPS}} \\\vdots & \vdots & \ddots & \vdots & \vdots & \vdots & \ddots & \vdots \\{d\;\Phi_{k,1}^{BDS}} & {d\;\Phi_{k,2}^{BDS}} & \cdots & {d\;\Phi_{k,n}^{BDS}} & {d\;\Phi_{k,1}^{GPS}} & {d\;\Phi_{k,2}^{GPS}} & \cdots & {d\;\Phi_{k,m}^{GPS}}\end{matrix} \right\rbrack_{t_{0}}$

wherein, each row represents a partition, and different columnsrepresent partition comprehensive corrections of GPS satellites and BDSsatellites in each partition. From time t0 to time t1, within theeffective time of the partition comprehensive correction, the partitioncomprehensive correction of each satellite may be calculated by thefollowing equation:dΦ _(ti) =dΦ _(t)0

The above correction parameters generated by the correction parametersinformation generating apparatus at the observation station side aretransported to the apparatus for superimposing, encoding andbroadcasting of message parameters at the base station side. Theapparatus for superimposing, encoding and broadcasting of messageparameters superimposes one or more of these correction parameters withthe basic navigation message as needed by way of protocolsuperimposition.

FIG. 1A schematically shows the structure of a correction parametersinformation generating apparatus 100. As shown in FIG. 1A, thecorrection parameters information generating apparatus 100 includes anorbit correction generation unit 101, a clock difference correctiongeneration unit 102, an ionosphere correction generation unit 103, apartition comprehensive correction generation unit 104 and a correctionparameters output unit 105.

The orbit correction generation unit 101, the clock differencecorrection generation unit 102, the ionosphere correction generationunit 103 and the partition comprehensive correction generation unit 104respectively generate an orbit correction, a clock differencecorrection, an ionosphere correction and a partition comprehensivecorrection as needed, the generated correction parameters are input tothe correction parameters output unit 105, and the correction parametersoutput unit 105 outputs these correction parameters to the base stationas needed for performing subsequent processes such as protocolsuperimposition, encoding, broadcasting and the like.

FIG. 2 schematically shows the flow of protocol superimposition. In FIG.2, A1 represents the superimposed orbit correction x₁, A2 represents thesuperimposed clock difference correction x₂, A3 represents thesuperimposed ionosphere correction x₃, and A4 represents thesuperimposed partition comprehensive correction x₄.

The protocol superimposition can be a combination of multiplesuperimpositions of different correction parameters, for example:

(1) The clock difference correction, the partition comprehensivecorrection (or the partition correction, the comprehensive correction)are superimposed on the basis of the basic navigation message. Forexample, the clock difference correction and the partition comprehensivecorrection may be solved accordingly by way of iteration. The specificsteps of the protocol superimposition include:

S11 of generating a clock difference correction x₂: superimposing theclock difference correction on the basis of the basic navigationmessage, its observation equation is abbreviated as follows:f(x ₂)=ρ+c·δt−c·(δt ^(s) −x ₂)+T  (a)wherein ρ is the theoretical satellite-earth distance, and δt,δt^(s) arethe clock difference of the observation station and the satellite clockdifference in the basic navigation message respectively, T is thetroposphere delay, x₂ is the satellite clock difference correction, andc is the speed of light. In equation (a), the satellite clock differencecorrection x₂ can be obtained by way of iterative calculation;S12 of generating a partition comprehensive correction x₄: on the basisof step S11, superimposing the partition comprehensive correction, theobservation equation is abbreviated as follows:f(x ₄ |x ₂)=ρ+c·δt−c·(δt ^(s) −x ₂)+T+x ₄  (b)wherein x₄ is the partition comprehensive correction, x₄|x₂ representsthat the partition comprehensive correction x₄ is solved on the basis ofx₂ (that is, on the basis of the satellite clock difference correctionx₂ having been obtained). In equation (b), the partition comprehensivecorrection x₄ can be obtained by way of iterative calculation.

(2) The orbit correction, the clock difference correction and thepartition comprehensive correction are superimposed on the basis of thebasic navigation message, the orbit correction (or satellite orbitcorrection), the clock difference correction and the partitioncomprehensive correction are solved accordingly by way of iteration. Thespecific steps of the protocol superimposition include:

S21 of generating an orbit correction x₁: superimposing the orbitcorrection on the basis of the basic navigation message, its observationequation is abbreviated as follows:f(x ₁)=ρ+Δρ(x ₁)+c·δt−c·δt ^(s) +T  (c)wherein Δρ(x₁) is the correction for the theoretical satellite-earthdistance and is a function of the satellite orbit correction x₁. Themeanings of other variables are the same as above, and will no longer bedescribed here. In equation (c), the satellite orbit correction x₁ canbe obtained by way of iterative calculation;S22 of generating a clock difference correction x₂: on the basis of stepS21, superimposing the clock difference correction x₂, the observationequation is abbreviated as follows:f(x ₂ |x ₁)=ρ+Δρ(x ₁)+c·δt−c·(δt ^(s) −x ₂)+T  (d)wherein x₂|x₁ represents that clock difference correction x₂ is solvedon the basis of x₁ (that is, on the basis of the satellite orbitcorrection x₁ having been obtained). The meanings of other variables arethe same as above, and will no longer be described here. In equation(d), the clock difference correction x₂ can be obtained by way ofiterative calculation;S23 of generating a partition comprehensive correction x₄: on the basisof step S22, further superimposing the partition comprehensivecorrection, the observation equation is abbreviated as follows:f(x ₄ |x _(1,2))=ρ+Δρ(x ₁)+c·δt−c·(δt ^(s) −x ₂)+T+x ₄  (e)wherein x₄ represents the partition comprehensive correction, x₄|x_(1,2)represents the partition comprehensive correction x₄ is solved on thebasis of x₁ and x₂ (that is, on the basis of the satellite orbitcorrection x₁ and the satellite clock difference correction x₂ havingbeen obtained). The meanings of other variables are the same as above,and will no longer be described here. In equation (e), the partitioncomprehensive correction x₄ can be obtained by way of iterativecalculation.

(3) The orbit correction and the partition comprehensive correction aresuperimposed on the basis of the basic navigation message, and the orbitcorrection and the partition comprehensive correction are solvedaccordingly by way of iteration. The specific steps of the protocolsuperimposition include:

S31 of generating an orbit correction x₁: it is the same as step S21,and therefore will no longer be described here;

S32 of generating a partition comprehensive correction x₄: on the basisof step S31, superimposing the partition comprehensive correction, theobservation equation is abbreviated as follows:f(x ₄ |x ₁)=ρ+Δρ(x ₁)+c·δt−c·δt ^(s) +T+x ₄  (g)wherein x₄|x₁ represents the partition comprehensive correction x₄ issolved on the basis of x₁ (that is, on the basis of the satellite orbitcorrection x₁ having been obtained). The meanings of other variables arethe same as above, and will no longer be described here. In equation(g), the partition comprehensive correction x₄ can be obtained by way ofiterative calculation.

(4) The ionosphere correction and the partition comprehensive correctionare superimposed on the basis of the basic navigation message, and theionosphere correction and the partition comprehensive correction aresolved accordingly. The specific steps of the protocol superimpositioninclude:

S41 of generating an ionosphere correction x₃: superimposing theionosphere correction on the basis of the basic navigation message, theobservation equation is abbreviated as follows:f(x ₃)=ρ+c·δt−c·δt ^(s) +T+x ₃(b,l)  (h)wherein x₃(b,l) represents that the ionosphere correction x₃ is afunction of latitude and longitude (b,l), and the meanings of othervariables are the same as above and will no longer be described here.Multiple observation stations obtain the ionosphere delay amount byusing pseudorange observation values (the pseudorange observation valuemay be the original pseudorange observation value P, or may be thepseudorange observation value P(x) corrected by the correctionparameters, which is not limited by the embodiment of the presentinvention) of multiple frequency points within a certain period of time,and generates an ionosphere grid model or an 8-parameter model or a14-parameter model by modeling to obtain an ionosphere correction x₃(b,l), so as to generate an ionosphere correction x₃;S42 of generating a partition comprehensive correction x₄: on the basisof step S41, further superimposing the partition comprehensivecorrection, the observation equation is abbreviated as follows:f(x ₄ |x ₃)=ρ+c·δt−c·δt ^(s) +T+x ₃(b,l)+x ₄  (e)wherein x₄|x₃ represents that the partition comprehensive correction x₄is solved on the basis of x₃ (that is, on the basis of the ionospherecorrection x₃ having been obtained). The meanings of other variables arethe same as above, and will no longer be described here. In equation(e), the partition comprehensive correction x₄ can be obtained by way ofiterative calculation;

(5) The orbit correction, the ionosphere correction and the partitioncomprehensive correction are superimposed on the basis of the basicnavigation message, and the orbit correction, the ionosphere correctionand the partition comprehensive correction are solved accordingly. Thespecific steps of the protocol superimposition include:

S51 of generating an orbit correction x₁: it is the same as step S21,and therefore will no longer be described here;

S52 of generating an ionosphere correction x₃: on the basis of step S51,superimposing the ionosphere correction, the observation equation isabbreviated as follows:f(x ₃ |x ₁)=ρ+Δρ(x ₁)+c·δt−c·δt ^(s) +T+x ₃(b,l)  (i)wherein x₃|x₁ represents that the ionosphere correction x₃ is solved onthe basis of x₁ (that is, on the basis of the orbit correction x₁ havingbeen obtained) and the meanings of other variables are the same as aboveand will no longer be described here;S53 of generating a partition comprehensive correction x₄: on the basisof step S52, further superimposing the partition comprehensivecorrection, the observation equation is abbreviated as follows:f(x ₄ |x _(1,3))=ρ+Δρ(x ₁)+c·δt−c·δt ^(s) +T+x ₃(b,l)+x ₄  (b)wherein x₄|x_(1,3) represents that the partition comprehensivecorrection x₄ is solved on the basis of x₁ and x₃ (that is, on the basisof the satellite orbit correction x₁ and the ionosphere correction x₃having been obtained). The meanings of other variables are the same asabove, and will no longer be described here. In equation (j), thepartition comprehensive correction x₄ can be obtained by way ofiterative calculation.

(6) The clock difference correction, the ionosphere correction and thepartition comprehensive correction are superimposed on the basis of thebasic navigation message, and the clock difference correction, theionosphere correction and the partition comprehensive correction aresolved accordingly. The specific steps of the protocol superimpositioninclude:

S61 of generating a clock difference correction x₂: it is the same asstep S11, and therefore will no longer be described here;

S62 of generating an ionosphere correction x₃: on the basis of step S61,superimposing the ionosphere correction, the observation equation isabbreviated as follows:f(x ₃ |x ₂)=ρ+c·δt−c·(δt ^(s) −x ₂)+T+x ₃(b,l)  (k)wherein x₃|x₂ represents that the ionosphere correction x₃ is solved onthe basis of x₂ (that is, on the basis of the clock differencecorrection x₂ having been obtained) and the meanings of other variablesare the same as above and will no longer be described here;S63 of generating a partition comprehensive correction x₄: on the basisof step S62, further superimposing the partition comprehensivecorrection, the observation equation is abbreviated as follows:f(x ₄ |x _(2,3))=ρ+c·δt−c·(δt ^(s) −x ₂)+T+x ₃(b,l)+x ₄  (m)wherein x₄|x_(2,3) represents that the partition comprehensivecorrection x₄ is solved on the basis of x₂ and x₃ (that is, on the basisof the clock difference correction x₂ and the ionosphere correction x₃having been obtained). The meanings of other variables are the same asabove, and will no longer be described here. In equation (m), thepartition comprehensive correction x₄ can be obtained by way ofiterative calculation.

(7) The orbit correction, the clock difference correction, theionosphere correction and the partition comprehensive correction aresuperimposed on the basis of the basic navigation message, and the orbitcorrection, the clock difference correction, the ionosphere correctionand the partition comprehensive correction are solved accordingly. Thespecific steps of the protocol superimposition include:

S71 of generating an orbit correction x₁: it is the same as step S21,and therefore will no longer be described here;

S72 of generating a clock difference correction x₂: it is the same asstep S22, and therefore will no longer be described here;

S73 of generating an ionosphere correction x₃: on the basis of step S72,further superimposing the ionosphere correction, the observationequation is abbreviated as follows:f(x ₃ |x _(1,2))=ρ+Δρ(x ₁)+c·δt−c·(δt ^(s) −x ₂)+T+x ₃(b,l)  (n)wherein x₃|x_(1,2) represents that the ionosphere correction x₃ issolved on the basis of x₁ and x₂ (that is, on the basis of the satelliteorbit correction x₁ and the clock difference correction x₂ having beenobtained), and the meanings of other variables are the same as above andwill no longer be described here;S74 of generating a partition comprehensive correction x₄: on the basisof step S73, further superimposing the partition comprehensivecorrection, the observation equation is abbreviated as follows:f(x ₄ |x _(1,2,3))=ρ+Δρ(x ₁)+c·δt−c·(δt ^(s) −x ₂)+T+x ₃(b,l)+x ₄  (y)wherein x₄|x_(1,2,3) represents that the partition comprehensivecorrection x₄ is solved on the basis of x₁, x₂ and x₃ (that is, on thebasis of the satellite orbit correction x₁, the clock differencecorrection x₂ and the ionosphere correction x₃ having been obtained).The meanings of other variables are the same as above, and will nolonger be described here. In equation (y), the partition comprehensivecorrection x₄ can be obtained by way of iterative calculation.

It should be noted that the above examples (1)-(7) can all be applied toa single-frequency receiver and a multi-frequency receiver (such as adual-frequency receiver and a tri-frequency receiver), which is notlimited by the embodiment of the present invention. It should be furthernoted that: 1. the partition comprehensive correction x₄ includes, butis not limited to, at least one of a Beidou partition comprehensivecorrection or a GPS partition comprehensive correction; the ionosphericcorrection x₃ uses models including, but being not limited to, a gridionosphere model, an 8-parameter model or a 14-parameter model, etc.,preferably uses the grid ionosphere model; 2. the orbit correction isalso called the satellite orbit correction, and the clock differencecorrection is also called the satellite clock difference correction,which will no longer be described throughout the description; 3. the wayof iteration or the way of iterative calculation mentioned in theembodiment of the present invention is only an example and not alimitation, and in other embodiments, a numerical calculation methodsuch as recursion may be used, and a calculation method such asintegration may further be used, on which the embodiment of the presentinvention does not impose any limitation, and in actual practice, thoseskilled in the art can reasonably make a choice as needed.

According to an embodiment of the present invention, in order to improvethe accuracy of positioning, correction parameters (for example,including an orbit correction, a clock difference correction, anionosphere correction, or a partition comprehensive correction(including a troposphere correction, a space segment correction and anenvironment segment correction)) are defined and modeled, and correctionparameters can provide multiple types of user error correction modessuch as DGNSS1 (clock difference correction), DGNSS2 (orbit correction,clock difference correction), DGNSS3 (orbit correction, clock differencecorrection, ionosphere correction), D+PPGNSS1 (clock differencecorrection, comprehensive correction or partition comprehensivecorrection), D+PPGNSS2 (orbit correction, clock difference correction,comprehensive correction or partition comprehensive correction),D+PPGNSS3 (orbit correction, clock difference correction, ionospherecorrection, comprehensive correction or partition comprehensivecorrection), D+PPGNSS3 (clock difference correction, comprehensivecorrection or partition comprehensive correction), includingsingle-frequency, dual-frequency, tri-frequency receiver positioning,and including, but not limited to, GNSS single Beidou, single GPS andBeidou-GPS combined positioning. By superimposing the partitioncomprehensive correction, the decimeter-level positioning can berealized.

After determining the correction parameters such as the orbitcorrection, the clock difference correction, the ionosphere correctionand the partition comprehensive correction, the apparatus forsuperimposing, encoding and broadcasting of message parameters furtherset the broadcast frequencies and the broadcast strategies of respectiveparameters based on, on one hand, the consideration of the resourcelimitation of the message and the resource limitation of the satellitecommunication link Additionally, on the other hand, the consideration ofthe accuracy attenuations in respective update periods of respectivecorrection parameters.

By employing the aforementioned correction parameters, the improvedaccuracy of positioning can be achieved in a wide range. Thecorresponding representation symbols of respective parameters (includingcorrection parameters) in the message and the specific design typicalvalues of respective parameters can be seen in the following table. Thespecific design values can also be adjusted suitably in conjunction withthe communication capability.

Representation Number Quantization Parameter name symbol of bits unitRange Unit Satellite clock difference Δt_(i) 13* 0.1 ±409.6 metercorrection Satellite clock difference Δt_(resi)  4* 2-7 ±0.0625 metercorrection residue User distance accuracy  

  4 1 0-15   — identifier User differential distance  

  4 1 0-15   — accuracy identifier Orbit Satellite ΔX 12* 2-5 ±64 metercorrection broadcast ephemeris correction ΔY 12* 2-5 ±64 meter ΔZ 12*2-5 ±64 meter Equivalent  

  4 1 0-15   — distance error status identifier of the ephemeriscorrection Ionosphere grid correction dτ_(i) 9 2-3 0-63.625 meter Gridpoint ionosphere  

  4 1 0-15    — vertical delay correction error flag Partitioncomprehensive ΔT_(ij)  8* 2-4 ±8 nanosecond correction GPS partitionΔTG_(ij)  8* 2-4 ±8 nanosecond comprehensive correction Other Area AREAI30  1 — — auxiliary identifier information Satellite BDIDI 63  1 — —identifier GPS area AREAGI 30  1 — — identifier GPS GPSI 36  1 — —satellite identifier Note: The parameters with *are represented by two'scomplements, and the highest bit is the sign bit.

The GPS partition comprehensive correction (ΔTGij) is the same as thepartition comprehensive correction (ΔTij) in terms of definition andusage. The partition comprehensive correction ΔTGij of each satellite ineach area indicates the comprehensive correction value of the j-th GPSsatellite in the i-th area at an epoch time. The area identifier (AREAI)indicates the area where the broadcast partition comprehensivecorrection is located. The number of area identifiers broadcast by thesystem corresponds to the defined integer number of partitions. When thecorresponding information bit is “1”, it indicates that thecorresponding partition comprehensive correction parameters isbroadcast; when it is “0”, it indicates that broadcasting is notperformed. Each satellite broadcasts partition comprehensive correctionsof a certain number of partitions. The correspondence between thespecific satellite code and the broadcast partition code can use thetypical broadcast strategy shown in the following table. The executionof superimposition of correction parameters is not limited thereto, andthe user perform identification according to identification bits.

Typical example of broadcast strategy for partition comprehensivecorrections

Satellite code Partition code Description SAT1 1~8, 11  140-degreeGEOsatellite SAT2 1, 9, 12~18   80-degree GEO satellite SAT31, 7~14 110.5-degree GEO satellite SAT4 1~8, 11   160-degree GEOsatellite SAT5 9, 10, 12~18 58.75-degree GEO satellite

The satellite identifier (BDIDI) indicates the satellite correspondingto the broadcast satellite orbit correction and partition comprehensivecorrection. The system broadcasts a total of 63 bits of satelliteidentifiers, corresponding to 63 Beidou satellites. When thecorresponding information bit is “1”, it indicates that the correctionparameters of the corresponding satellite is broadcast; when it is “0”,it indicates that broadcasting is not performed.

The user may decide to perform the positioning resolution using thecorrection parameters of a certain satellite in a certain area based onthe above-mentioned auxiliary information such as area identifiers,satellite identifiers and the like.

The GPS area identifier (AREAGI) indicates the area where the broadcastGPS partition comprehensive correction is located. The definition ofarea identifiers broadcast by the system corresponds to the definedinteger number of partitions. When the corresponding information bit is“1”, it indicates that the corresponding partition comprehensivecorrection parameters is broadcast; when it is “0”, it indicates thatbroadcasting is not performed.

The GPS satellite identifier (GPSI) indicates the satellitecorresponding to the broadcast GPS partition comprehensive correction.The system broadcasts a total of 36 bits of satellite identifiers,corresponding to 36 GPS satellites. When the corresponding informationbit is “1”, it indicates that the correction parameters of thecorresponding satellite is broadcast; when it is “0”, it indicates thatbroadcasting is not performed.

According to the scheme of the embodiment of the present invention, thebroadcast quantity of correction parameters can be controlled to be lessthan 100 bps on average, so that broadcasting of correction parameterscan be implemented in the 250-500 bps navigation message. Higher orlower broadcast frequencies of parameters may also be used, thusreducing the initialization time, or controlling the acceptable initialusage time extension.

In addition, considering the broadcast capabilities of the system andthe communication link, the broadcast frequencies thereof cannot be toohigh. However, the broadcast frequency being low will cause the loss ofaccuracy of corrections. On the basis of the accurate calculation ofcorrections, the accuracy of user positioning and the broadcastefficiency of the system are compared under different broadcastfrequencies, thereby determining the appropriate broadcast frequency ofthe correction parameters, and the smooth control is performed incombination with the different fast or slow broadcast frequencies of thecorrection parameters. Thus, fast speed, fast frequency and highaccuracy can all be achieved.

Based on the above correction parameters model, the broadcastfrequencies of the parameters can be designed as: the orbit correctionparameters being 3˜6 minutes; the clock difference correction parametersbeing 18 seconds˜2 minutes; the ionosphere correction parameters being3˜6 minutes; the comprehensive correction parameters or the partitioncomprehensive correction parameters being 30˜180 seconds.

For example, the specific broadcast frequencies selected according tothe performance requirements may be as follows: the orbit correction isof the frequency of 6 minutes; the error of the clock differencecorrection within the frequency of 2 minutes can be controlled at 0.2meters; and the error of the partition correction of the frequency of 3minutes can be controlled at about 0.06 meters, as the meanings of thenumbers in the above table.

The broadcast strategy only has to ensure that a predetermined accuracycan obtain within this range when it is broadcast to the user forreception and use. The accuracies of respective correction parametersare reduced within their respective update periods: therefore, if thefrequency of the clock difference correction is within 2 minutes and thefrequency of the partition correction is within 3 minutes, theperformance can be guaranteed. Generally, the higher the broadcastfrequency, the better the performance. Typical values are like that theorbit correction is of frequency of 6 minutes, the clock differencecorrection is of frequency of 18 seconds, and the partition correctionis of frequency of 36 seconds. In this way, while the quantity ofbroadcast is small, the performance can be guaranteed (meeting theaccuracy requirement), and the initialization time for the user to enterthe substantially high-accuracy working state will not be made too long,and the user receives the measurement with high accuracy, the processingtime is basically matched, and the user's use area is large, so as toachieve wide-area differential performance improvement.

The update of the correction parameters can be combined with theaforementioned protocol superimposition (protocol superimposition is thesuperimposition of correction parameters, for example, example(1)-example (7) are also various superimposition combinations ofdifferent correction parameters). Details are as follows.

For example, FIG. 3A is a timing matching schematic diagram ofsuperimposing an orbit correction and a partition comprehensivecorrection on the basis of a basic navigation message, corresponding tothe above example (3). As shown in FIG. 3A, the update period of theorbit correction is m minutes, where m is a positive number and 3≤m≤6.Within the period of time between the previous broadcast ephemerisupdate time t and the current broadcast ephemeris update time t0: thetime m′ is the update time point of the last orbit correction; withinthe period of time between the current broadcast ephemeris update timet0 and the next broadcast ephemeris update time t1: the time t0+b1 isthe update time point of one partition comprehensive correction, thetime t0+b2 is the update time point of another partition comprehensivecorrection, and the time m′+m is the update time point of the firstorbit correction (one valid period of time is from m′ to m′+m, the nextvalid period of time is from m′+m to m′+2m, and so on, which will nolonger be described), the time m′+2m is the update time point of thesecond orbit correction, where b1 and b2 are both positive numbers, andt0+b1<m′+m<t0+b2<m′+2m; specific examples are as follows:

For example, at the time t0+b1, superimposing the orbit correction andthe partition comprehensive correction on the basis of the basicnavigation message corresponding to the above example (3) comprises: 1.based on the basic navigation message generated at the previousbroadcast ephemeris update time t, solving the orbit correction at thetime m′ through the above equation (c); 2. based on the basic navigationmessage generated at the current broadcast ephemeris update time t0 andthe orbit correction at time m′ obtained by solution, solving thepartition comprehensive correction through the above equation (g).

As in another example, at the time t0+b2, superimposing the orbitcorrection and the partition comprehensive correction on the basis ofthe basic navigation message corresponding to the above example (3)comprises: 1. based on the basic navigation message generated at thecurrent broadcast ephemeris update time t0, solving the orbit correctionat the time m′+m through the above equation (c); 2. based on the basicnavigation message generated at the current broadcast ephemeris updatetime t0 and the orbit correction at the time m′+m obtained by solution,solving the partition comprehensive correction through the aboveequation (g).

It should be Noted as Follows:

1. The time t0+b1, the time m′, the time t0+b2 and the time m′+mmentioned in the embodiment of the present invention are merely examplesand not limitation. In the actual practice, it is sufficient to meet thefollowing requirements: within the period of time between the currentbroadcast ephemeris update time t0 and the next broadcast ephemerisupdate time t1, for the time t0+d, superimposing the orbit correctionand the partition comprehensive correction on the basis of the basicnavigation message comprises: 1) if t0+d<m′+m, at first, based on thebasic navigation message generated at the previous broadcast ephemerisupdate time t, solving the orbit correction at the time m′ through theabove equation (c); then, based on the basic navigation messagegenerated at the current broadcast ephemeris update time t0 and theorbit correction at the time m′ obtained by solution, solving thepartition comprehensive correction through the above equation (g); 2) ifm′+(n)*m≤t0+d<m′+(n+1)*m, at first, based on the basic navigationmessage generated at the current broadcast ephemeris update time t0,solving the orbit correction at the time m′+n*m through the aboveequation (c); then, based on the basic navigation message generated atthe current broadcast ephemeris update time t0 and the orbit correctionat the time m′+n*m obtained by solution, solving the partitioncomprehensive correction through the above equation (g);

wherein d is a positive number and n is a positive integer.

2. The times such as time t0+b1, the time m′, the time t0+b2 and thetime m′+m for the identification shown in FIG. 3A are all used to onlydescribe the embodiment instead of the actual time identification, andthe length of the identification in FIG. 3A does not represent theactual length of the identification.

For example, FIG. 3B is a timing matching schematic diagram ofsuperimposing a clock difference correction and a partitioncomprehensive correction on the basis of a basic navigation message,corresponding to the above example (1). In one implementation, theupdate frequency of the partition comprehensive correction is fasterthan the update frequency of the clock difference correction. As shownin FIG. 3B, the update period of the clock difference correction is aminutes, where a is a positive number and 0.3≤a≤2. With the period oftime between the previous broadcast ephemeris update time t and thecurrent broadcast ephemeris update time t0: the time a′ is the updatetime point of the last clock difference correction; within the period oftime between the current broadcast ephemeris update time t0 and the nextbroadcast ephemeris update time t1: the time t0+b1 is the update timepoint of one partition comprehensive correction, the time t0+b2 is theupdate time point of another partition comprehensive correction, thetime a′+a is the update time point of the first clock differencecorrection (one valid period of time is from a′ to a′+a, the next validperiod of time is from a′+a to a′+2a and so on, which will no longer bedescribed), the time a′+2a is the update time point of the second clockdifference correction, wherein b1 and b2 are both positive numbers, andt0+b1<a′+a≤t0+b2<a′+2a. Specific examples are as follows:

For example, at the time t0+b1, superimposing the orbit correction andthe partition comprehensive correction on the basis of the basicnavigation message corresponding to the above example (1) comprises: 1.based on the basic navigation message generated at the previousbroadcast ephemeris update time t, solving the clock differencecorrection at time a′ through the above equation (a); 2. based on thebasic navigation message generated at the current broadcast ephemerisupdate time t0 and the clock difference correction at the time a′obtained by solution, solving the partition comprehensive correctionthrough the above equation (b).

As in another example, at the time t0+b2, superimposing the clockdifference correction and the partition comprehensive correction on thebasis of the basic navigation message corresponding to the above example(1) comprises: 1. based on the basic navigation message generated at thecurrent broadcast ephemeris update time t0, solving the clock differencecorrection at the time a′+a through the above equation (a); 2. based onthe basic navigation message generated at the current broadcastephemeris update time t0 and the clock difference correction at the timea′+a obtained by solution, solving the partition comprehensivecorrection through the above equation (b).

It should be Noted as Follows:

1. The time identifiers such as the time t0+b1, the time a′, the timet0+b2 and the time a′+a mentioned in the embodiment of the presentinvention are only examples and not limitation. In the actual practice,it is sufficient to meet the following requirements: within the periodof time between the current broadcast ephemeris update time t0 and thenext broadcast ephemeris update time t1, for the time t0+d,superimposing the clock difference correction and the partitioncomprehensive correction on the basis of the basic navigation messagecomprises: 1) if t0+d<a′+a, at first, based on the basic navigationmessage generated at the previous broadcast ephemeris update time t,solving the clock difference correction at the time a′ through the aboveequation (a); then, based on the basic navigation message generated atthe current broadcast ephemeris time t0 and the clock differencecorrection at the time a′ obtained by solution, solving the partitioncomprehensive correction through the above equation (b); 2) ifa′+(n)*a≤t0+d<a′+(n+1)*a, at first, based on the basic navigationmessage generated at the current broadcast ephemeris update time t0,solving the clock difference correction at the time a′+(n)*a through theabove equation (a); then, based on the basic navigation messagegenerated at the current broadcast ephemeris update time t0 and theclock difference correction at the time a′+(n)*a obtained by solution,solving the partition comprehensive correction through the aboveequation (b), wherein d is a positive number and n is a positiveinteger.

2. The time identifiers such as the time t0+b1, the time a′, the timet0+b2 and the time a′+a for the identification shown in FIG. 3B are allused to only describe the embodiment, but not the actual timeidentifiers, and the length of the identification in FIG. 3B does notrepresent the actual length of the identification.

3. The update period of the clock difference correction can be, forexample, 18 seconds. For the Beidou system, the satellite clockdifference corrections of the frequency points B1 and B2 are different,and each frequency point only broadcasts the satellite clock differencecorrection corresponding to the frequency point.

For example, in another implementation, the update frequency of thepartition comprehensive correction may be slower than the updatefrequency of the clock difference correction: FIG. 3C is another timingmatching schematic diagram of superimposing a clock differencecorrection and a partition comprehensive correction on the basis of abasic navigation message, corresponding to the above example (1). Asshown in FIG. 3C, the update period of the clock difference correctionis a minutes, where a is a positive number and 0.3≤a≤2. Within theperiod of time between the previous broadcast ephemeris update time tand the current broadcast ephemeris update time t0: the time a′ is theupdate time point of the last clock difference correction; within theperiod of time between the current broadcast ephemeris update time t0and the next broadcast ephemeris update time t1: the time t0+d is theupdate time point of one partition comprehensive correction, andmeantime a′+(n)*a≤t0+d<a′+(n+1)*a is met, where d is a positive numberand n is a positive integer. Specific examples are as follows:

At the time t0+d, superimposing the clock difference correction and thepartition comprehensive correction on the basis of the basic navigationmessage corresponding to the above example (1) comprises: at first,based on the basic navigation message generated at the current broadcastephemeris update time t0, solving the clock difference correction attime a′+(n)*a through the above equation (a); then, based on the basicnavigation message generated at the current broadcast ephemeris updatetime t0 and the clock difference correction at the time a′+(n)*aobtained by solution, solving the partition comprehensive correctionthrough the above equation (b).

It should be noted that the time identifiers such as the time t0+b1 andthe time a′+a for the identification shown in FIG. 3C are all used toonly describe the embodiment, but not the actual time identifiers, andthe length of the identification in FIG. 3B does not represent theactual length of the identification.

For example, in one embodiment, the update frequency of the partitioncomprehensive correction is faster than the update frequency of theclock difference correction, and the update frequency of the clockdifference correction is faster than the update frequency of the orbitcorrection, as shown in FIG. 3D. FIG. 3D is a timing matching schematicdiagram of superimposing an orbit correction, a clock differencecorrection and a partition comprehensive correction on the basis of abasic navigation message corresponding to the above example (2). Asshown in FIG. 3D, the update period of the orbit correction is mminutes, and the update period of the clock difference correction is aminutes, where m and a are positive numbers, and 3≤m≤6, 0.3≤a<m. Withinthe period of time between the previous broadcast ephemeris update timet and the current broadcast ephemeris update time t0: the time m′ is theupdate time point of the last orbit correction, and the time a′ is theupdate time point of the last clock difference correction; within theperiod of time between the current broadcast ephemeris update time t0and the next broadcast ephemeris update time t1: the time t0+b1 is theupdate time point of one partition comprehensive correction, the timet0+b2 is the update time point of another partition comprehensivecorrection, the time t0+b3 is the update time point of yet anotherpartition comprehensive correction, the time m′+m is the update timepoint of the first orbit correction, and the time a′+a is the updatetime of the first clock difference correction, wherein b1, b2 and b3 areall positive numbers, and t0+b1<a′+a<m′+m, a′+h*a<t0+b2<m′+m,(t0+b2)−(a′+h*a)<a, m′+e*m<a′+f*a<t0+b3<m′+(e+1)*m, (t0+b3)−(a′+f*a)<a,where h, e and f are all positive integers. Specific examples are asfollows:

For example, at the time t0+b1, superimposing the orbit correction, theclock difference correction and the partition comprehensive correctionon the basis of the basic navigation message corresponding to the aboveexample (2) comprises: 1. based on the basic navigation messagegenerated at the previous broadcast ephemeris update time t, solving theorbit correction at the time m′ is through the above equation (c); 2.based on the basic navigation message generated the previous broadcastephemeris update time t and the orbit correction at the time m′ obtainedby solution, solving the clock difference correction at the time a′through the above equation (d); 3. based on the basic navigation messagegenerated at the current broadcast ephemeris update time t0 and theorbit correction at the time m′ obtained by solution, solving thepartition comprehensive correction through the above equation (e);

For example, at the time t0+b2, superimposing the orbit correction, theclock difference correction and the partition comprehensive correctionon the basis of the basic navigation message corresponding to the aboveexample (2) comprises: 1. based on the basic navigation messagegenerated at the previous broadcast ephemeris update time t, solving theorbit correction at the time m′ through the above equation (c); 2. basedon the basic navigation message generated at the current broadcastephemeris update time t0 and the orbit correction at the time m′obtained by solution, solving the clock difference correction at thetime a′+(h)*a through the above equation (d); 3. based on the basicnavigation message generated at the current broadcast ephemeris updatetime t0 and the orbit correction at the time m′ and the clock differencecorrection at the time a′+(h)*a obtained by solution, solving thepartition comprehensive correction through the above equation (e);

For example, at the time t0+b3, superimposing the orbit correction, theclock difference correction and the partition comprehensive correctionon the basis of the basic navigation message corresponding to the aboveexample (2) comprises: 1. based on the basic navigation messagegenerated at the current broadcast ephemeris update time t0, solving theorbit correction at the time m′+(e)*m through the above equation (c); 2.based on the basic navigation message generated at the current broadcastephemeris update time t0 and the orbit correction at the time m′+(e)*mobtained by solution, solving the clock difference correction at thetime a′+(f)*a through the above equation (d); 3. based on the basicnavigation message generated at the current broadcast ephemeris updatetime t0 and the orbit correction at the time m′+(e)*m and the clockdifference correction at the time a′+(f)*a obtained by solution, solvingthe partition comprehensive correction through the above equation (e);

For example, in one embodiment, the update frequency of the clockdifference correction is faster than the update frequency of thepartition comprehensive correction, and the update frequency of thepartition comprehensive correction is faster than the update frequencyof the orbit correction. FIG. 3E is another timing matching schematicdiagram of superimposing an orbit correction, a clock differencecorrection and a partition comprehensive correction on the basis of abasic navigation message, corresponding to the above example (2). Asshown in FIG. 3E, the update period of the orbit correction is mminutes, and the update period of the clock difference correction is aminutes, where m and a are positive numbers, and 3≤m≤6, 0.3≤a≤2. Withinthe period of time between the previous broadcast ephemeris update timet and the current broadcast ephemeris update time t0: the time m′ is theupdate time point of the last orbit correction, and the time a′ is theupdate time point of the last clock difference correction; within theperiod of time between the current broadcast ephemeris update time t0and the next broadcast ephemeris update time t1: the time t0+b1 is theupdate time point of one partition comprehensive correction, and thetime t0+b2 is the update time point of another partition comprehensivecorrection, where a′+h*a<t0+b1<m′+m, m′+e*m<a′+f*a<t0+b2<(e+1)*m,(t0+b1)−(a″+h*a)<a, (t0+b2)−(a′+f*a)<a, where b1, b2 are positivenumbers, and h, f, e are positive integer. Specific examples are asfollows:

For example, at the time t0+b1, superimposing the orbit correction, theclock difference correction and the partition comprehensive correctionon the basis of the basic navigation message corresponding to the aboveexample (2) comprises: at first, based on the basic navigation messagegenerated at the previous broadcast ephemeris update time t, solving theorbit correction at the time m′ through the above equation (c); then,based on the basic navigation message generated at the current broadcastephemeris update time t0 and the orbit correction at the time m′obtained by solution, solving the clock difference correction at timea′+h*a through the above equation (d), and finally, based on basicnavigation message generated at the current navigation ephemeris updatetime t0 and the orbit correction at the time m′ and the clock differencecorrection at the time a′+h*a obtained by solution, solving thepartition comprehensive correction through the above equation (e);

For example, at the time t0+b2, superimposing the orbit correction, theclock difference correction and the partition comprehensive correctionon the basis of the basic navigation message corresponding to the aboveexample (2) comprises: at first, based on the basic navigation messagegenerated at the current broadcast ephemeris update time t0, solving theorbit correction at the time m′+(e)*m through the above equation (c);then, based on the basic navigation message generated at the currentbroadcast ephemeris update time t0 and the orbit correction at the timem′+(e)*m obtained by solution, solving the clock difference correctionat the time a′+(f)*a through the above equation (d), and finally, basedon the basic navigation message generated at the current broadcastephemeris update time t0 and the orbit correction at time m′+(e)*m andthe clock correction at time a′+(f)*a obtained by solution, solving thepartition comprehensive correction through the above equation (e).

For the ionosphere correction, the update period can be, for example,3˜6 minutes. The ionosphere correction is the correction for thepropagation segment (or environment segment) error. As mentioned before,multiple observation stations obtain the ionosphere delay amount byusing pseudorange observation values (the pseudorange observation valuemay be the original pseudorange observation value P, or may be thepseudorange observation value P(x) corrected by the correctionparameters, which is not limited by the embodiment of the presentinvention) of multiple frequency points within a certain period of time,and generates an ionosphere grid model or an 8-parameter model or a14-parameter model by modeling to obtain an ionosphere correction x₃(b,l). Therefore, there is no need to perform the timing matching forthe ionosphere correction.

Therefore, for the example (5), the same parts between its timingmatching procedure and the timing matching procedure of the example (3)will no longer be described, the difference thereof is as follows:

For example, at the time t0+b1, superimposing the orbit correction, theionosphere correction and the partition comprehensive correction on thebasis of the basic navigation message corresponding to the above example(5) comprises: 2. based on the basic navigation message generated at thecurrent broadcast ephemeris update time t0 and the orbit correction atthe time m′ obtained by solution, solving the ionosphere correctionthrough the above equation (i); 3. based on the basic navigation messagegenerated at the current broadcast ephemeris update time t0 and theorbit correction at the time m′ obtained by solution and the ionospherecorrection, solving the partition comprehensive correction through theabove equation (j).

As another example, at the time t0+b2, superimposing the orbitcorrection, the ionosphere correction and the partition comprehensivecorrection on the basis of the basic navigation message corresponding tothe above example (5) comprises: 2. based on the basic navigationmessage generated at the current broadcast ephemeris update time t0 andthe orbit correction at the time m′+m obtained by solution, solving theionosphere correction through the above equation (i); 3. based on thebasic navigation message generated at the current broadcast ephemerisupdate time t0 and the orbit correction at the time m′+m obtained bysolution and the ionosphere correction, solving the partitioncomprehensive correction through the above equation (j).

For the example (6), the same parts between its timing matchingprocedure and the timing matching procedure of the example (1) will nolonger be described:

1) When the update frequency of the partition comprehensive correctionis faster than the update frequency of the clock difference correction,the difference thereof is as follows:

For example, at the time t0+b1, superimposing the orbit correction, theionosphere correction and the partition comprehensive correction on thebasis of the basic navigation message corresponding to the above example(6) comprises: 2. based on the basic navigation message generated at thecurrent broadcast ephemeris update time t0 and the clock differencecorrection at the time a′ obtained by solution, solving the ionospherecorrection through the above equation (k); 3. based on the basicnavigation message generated at the current broadcast ephemeris updatetime t0 and the clock difference correction at the time a′ obtained bysolution and the ionosphere correction, solving the partitioncomprehensive correction through the above equation (m);

For example, at the time t0+b1, superimposing the orbit correction, theionosphere correction and the partition comprehensive correction on thebasis of the basic navigation message corresponding to the above example(6) comprises: 2. based on the basic navigation message generated at thecurrent broadcast ephemeris update time t0 and the clock differencecorrection at time a′+a obtained by solution, solving the ionospherecorrection through the above equation (k); 3. based on the basicnavigation message generated at the current broadcast ephemeris updatetime t0 and the clock difference correction at time a′+a obtained bysolution and the ionosphere correction, solving the partitioncomprehensive correction through the above equation (m).

2) When the update frequency of the partition comprehensive correctionis slower than the update frequency of the clock difference correction,the difference thereof is as follows:

At the time t0+d, superimposing the clock difference correction, theionosphere correction and the partition comprehensive correction on thebasis of the basic navigation message corresponding to the above example(6) comprises: further based on basic navigation generated at thecurrent broadcast ephemeris update time t0 and the clock differencecorrection at the time a′+(n)*a obtained by solution, solving theionosphere correction through the above equation (k); finally, based onthe basic navigation message generated at the current broadcastephemeris update time t0 and the clock difference correction at the timea′+(n)*a obtained by solution and the ionosphere correction, solving thepartition comprehensive correction through the above equation (b).

For the example (7), the same parts between its timing matchingprocedure and the timing matching procedure of the example (3) will nolonger be described:

1) When the update frequency of the partition comprehensive correctionis faster than the update frequency of the clock difference correctionand the update frequency of the clock difference correction is fasterthan the update frequency of the orbit correction, the differencethereof is as follows:

For example, at the time t0+b1, superimposing the orbit correction, theclock difference correction, the ionosphere correction and the partitioncomprehensive correction based on the basic navigation messagecorresponding to the above example (7) comprises: 3. then, based on thebasic navigation message generated at the current broadcast ephemerisupdate time t0 and the orbit correction at the time m′ and the clockdifference correction time at the time a′ obtained by solution, solvingthe ionosphere correction through the above equation (n); 4. finally,based on the basic navigation message generated at the current broadcastephemeris update time t0 and the orbit correction at the time m′ and theclock difference correction at the time a′ obtained by solution and theionosphere correction, solving the partition comprehensive correctionthrough the above equation (y);

For example, at the time t0+b2, superimposing the orbit correction, theclock difference correction, the ionosphere correction and the partitioncomprehensive correction on the basis of the basic navigation messagecorresponding to the above example (7) comprises: 3. then, based on thebasic navigation message generated at the current broadcast ephemerisupdate time t0 and the orbit correction at the time m′ and the clockdifference correction at the time a′+h*a obtained by solution, solvingthe ionosphere correction through the above equation (n); 4. finally,based on the basic navigation message generated at the current broadcastephemeris update time t0 and the orbit correction at the time m′ and theclock difference correction at the time a′+h*a obtained by solution andthe ionosphere correction, solving the partition comprehensivecorrection through the above equation (y).

For example, at the time t0+b3, superimposing the orbit correction, theclock difference correction, the ionosphere correction and the partitioncomprehensive correction on the basis of the basic navigation messagecorresponding to the above example (7) comprises: 3. then, based on thebasic navigation message generated at the current broadcast ephemerisupdate time t0 and the orbit correction at the time m′+(e)*m and theclock difference correction at the time a′+(f)*a obtained by solution,solving the ionosphere correction through the above equation (n); 4.finally, based on the basic navigation message generated at the currentbroadcast ephemeris update time t0 and the orbit correction at the timem′+(e)*m and the clock difference correction at the time a′+(f)*a andthe ionosphere correction, solving the partition comprehensivecorrection through the above equation (y).

2) When the update frequency of the clock difference correction isfaster than the update frequency of the partition comprehensivecorrection and the update frequency of the partition comprehensivecorrection is faster than the update frequency of the orbit correction,the difference thereof is as follows:

For example, at the time t0+b1, superimposing the orbit correction, theclock difference correction, the ionosphere correction and the partitioncomprehensive correction on the basis of the basic navigation messagecorresponding to the above example (7) comprises: then, based on thebasic navigation message generated at the current broadcast ephemerisupdate time t0 and the orbit correction at the time m′ and the clockdifference correction at the time a′+h*a, solving the ionospherecorrection through the above equation (n); and finally, based on thebasic navigation message generated at the current broadcast ephemerisupdate time t0 and the orbit correction at the time m′ and the clockdifference correction at the time a′+h*a and the ionosphere correction,solving the partition comprehensive correction through the aboveequation (y);

For example, at the time t0+b2, superimposing the orbit correction, theclock difference correction, the ionosphere correction and the partitioncomprehensive correction on the basis of the basic navigation messagecorresponding to the above example (7) comprises: then, based on thebasic navigation message generated at the current broadcast ephemerisupdate time t0 and the orbit correction at the time m′+(e)*m and theclock difference correction at the time a′+(f)*a obtained by solution,solving the ionosphere correction by the above equation (n); andfinally, based on the basic navigation message generated at the currentbroadcast ephemeris update time t0 and the orbit correction at the timem′+(e)*m and the clock difference correction at the time a′+(f)*a andthe ionosphere correction, solving the partition comprehensivecorrection through the above equation (y).

It should be noted that when receiving and/or using the correctionparameters, the user end (receiver) needs to perform matching with thereceived correction parameters (including, but not limited to, matchingin time and matching on the type of correction parameters).

The partition comprehensive correction is the comprehensive correctionof a satellite currently observed in each partition. Limited by thesatellite-earth interface resources, and considering the impact of theupdate frequency of the partition comprehensive correction on theperformance, when the update time is less than 2 minutes, there is nosignificant difference in the accuracy of user positioning; after theupdate time exceeds 2 minutes, the accuracy of positioning dropssignificantly.

In order to meet the requirements of the broadcasting, the embodimentsof the present invention describe a procedure and a method of correctionparameters superimposition, and a matching procedure between them.

The use of multiple superimposition combinations of different correctionparameters (i.e., multiple protocol superimpositions) may enable theuser to achieve positioning requirements of different levels of accuracyunder different hardware and software environments. For example, afterthe protocol superimposes the partition comprehensive correction, thepositioning requirement of decimeter-accuracy can be realized.

When the protocol superimposition is applied to a satellite positioningsystem, it is required to broadcast the correction parameters to theuser in the form of a navigation message through a navigation satellite.Therefore, the satellite navigation system proposed by the presentinvention must consider the method and strategy of parameterarrangement. The message arrangement of the correction parameters needsto consider the following factors:

(1) the design of the message frame structure of the navigation messagein a compatible satellite navigation system;

(2) the use of unused fields (reserved bits) of the message resources toperform the arrangement;

(3) the loss of the message expression accuracy of the correctionparameters is less.

In view of the above factors, the present invention also provides amessage arrangement and broadcast method for an enhanced parameter in asatellite navigation system, which can fully utilize the remainingresources in the navigation message of the satellite navigation system,Additionally, in accordance with the repetition periods of respectivepages, superframes, main frames and sub-frames of the remainingresources, arrange the different correction parameters according totheir respective characteristics to be integrated with the navigationmessage and broadcast to the user. The message arrangement and broadcastmethod can be implemented by the above apparatus for superimposing,encoding and broadcasting of message parameters set at the base station,where the enhanced parameter is the correction parameters, and will nolonger be described throughout the description.

For example, the message broadcast apparatus 40 shown in FIG. 4 mayimplement functions of message encoding (arrangement) and broadcastsetting of the above apparatus for superimposing, encoding andbroadcasting of message parameters, and the message broadcast apparatus40 may also include a transmitter to implement the function oftransmitting a signal by the switch of the base station to satellites.

FIG. 4 shows a block diagram of the configuration of main units of amessage broadcast apparatus 40 for an enhanced parameter in a satellitenavigation system according to an embodiment of the present invention.

As shown in FIG. 4, the message broadcast apparatus 40 include aprocessor 401 and a transmitter 402. The processor 401 determines aninsertion position of the enhanced parameter in a reserved space in anavigation message frame structure model according to the byte size andthe broadcast frequency of the enhanced parameter that needs to bebroadcast, so as to perform the message arrangement of the enhancedparameter. The transmitter 402 uploads the arranged message to abroadcast satellite for broadcasting the message.

In the message broadcast apparatus 40, the navigation message framestructure model is defined by a superframe, a main frame and asub-frame, with each of superframes containing 120 main frames, each ofmain frames containing 5 sub-frames, each of sub-frames containing 10words and each of words containing 30 bits and lasting 0.06 second.Additionally, among the 5 sub-frames, sub-frame 1 is used to broadcastthe present satellite's basic navigation information of the satellitenavigation system, and information in a group of sub-frames 1 istransmitted by 10 pages in a time division manner, that is, onetransmission of the present satellite's basic navigation information isaccomplished by 10 pages composed of 10 sub-frames 1 (that is, a groupof sub-frames 1 constitutes a group of pages); sub-frame 2 to sub-frame4 are used to broadcast the integrity and differential information ofthe satellite navigation system, and information in respective groups ofsub-frames 2˜4 is transmitted by 6 pages respectively in a time divisionmanner, that is, the transmission of the integrity and differentialinformation of the satellite navigation system at one time isaccomplished respectively by 6 pages composed of 6 sub-frames 2˜4 (thatis, a group of sub-frames 2˜4 constitutes a group of pagesrespectively); and sub-frame 5 is used to broadcast all the satellitealmanacs, ionosphere information and time synchronization informationwith other systems of the satellite navigation system, and informationin a group of sub-frames 5 is transmitted by 120 pages in a timedivision manner, that is, one transmission of all the satellitealmanacs, ionosphere information and time synchronization informationwith other systems of the satellite navigation system is accomplished by120 pages composed of 120 sub-frames 5.

As described above, a satellite-based enhanced parameter is forimproving the accuracy of the system's real-time service, and itdifferentiates the main error sources such as satellite orbit error,satellite clock difference and ionosphere delay, and establishes a modelfor each type of error source for correcting errors of these parametersin the basic navigation. For example, taking the Beidou system as anexample, the satellite-based enhanced parameter may include satelliteclock difference correction parameters, satellite orbit correctionparameters, ionosphere correction parameters and partition comprehensivecorrection parameters, which will be described in detail hereinafter. Itshould be understood that the above-described satellite-based enhancedparameter is merely one example of an enhanced parameter for ease ofexplanation, rather than limiting the present invention thereto. Theinvention can also be applied to ground-based enhanced parameters.

In order to facilitate the understanding of the navigation message framestructure model as described above, the description will be made inconjunction with FIG. 5 in the following. FIG. 5 is a schematic diagramillustrating a navigation message frame structure model according to anembodiment of the present invention. As shown in FIG. 5, the navigationmessage frame structure is defined by a superframe, a main frame and asub-frame. Each of superframes is 180000 bits and lasts 6 minutes. Eachof superframes includes 120 main frames, as shown by main frame 1, mainframe 2 . . . main frame n . . . main frame 120 in FIG. 5. Each of mainframes is 1500 bits and lasts 3 seconds. Each of main frames includes 5sub-frames, as shown by sub-frame 1, sub-frame 2, sub-frame 3, sub-frame4 and sub-frame 5 in FIG. 5. Each of sub-frames is 300 bits and lasts0.6 seconds. Each of sub-frames further includes 10 words, as shown byword 1, word 2, . . . , word 10 in FIG. 5. Each of words is 30 bits andlasts 0.06 seconds. Each of words includes two portions, i.e.,navigation message information (or data) and a check code. Noerror-correction coding is performed on the first 15 bits of the firstword (i.e., word 1) of each sub-frame, and the last 11 bits of theinformation are error-corrected by employing the BCH (15,11,1) manner.As shown in FIG. 5, word 1 contains 26-bit information bits and a 4-bitcheck code. The other 9 words (i.e., words 2˜10) of each sub-frame areerror-correction coded by employing the BCH (15,11,1) plus interleavingmanner. As shown in FIG. 5, each of words 2˜10 contains 22-bitinformation bits and an 8-bit check code.

To illustrate the message arrangement in the navigation message framestructure model, refer to FIG. 6. FIG. 6 is a schematic diagramillustrating navigation message information contents in a navigationmessage frame structure model according to an embodiment of the presentinvention. Taking the Beidou system as an example, the navigationmessage includes the present satellite's basic navigation information,all the satellite almanacs, the time synchronization information withother systems, the integrity and differential information of the Beidousystem and ionosphere information. Specifically, as shown in FIG. 6,sub-frame 1 is used to broadcast the present satellite's basicnavigation information, sub-frames 2˜4 are used to broadcast theintegrity and differential information of the Beidou system, andsub-frame 5 is used to broadcast all the satellite almanacs, theionosphere information and the time synchronization information withother systems.

Since the broadcast frequencies (or update periods) of these navigationinformation are different, different broadcast frequencies can beachieved by making the sub-frames broadcasting them respectivelyconstitute separate pages. As shown in FIG. 6, completing onetransmission of the present satellite's basic navigation informationrequires a group of pages of sub-frame 1 to broadcast, in which a groupof pages of sub-frame 1 consists of 10 pages (that is, transmitted in atime division manner), that is, one transmission of the presentsatellite's basic navigation information is completed by ten continuoussub-frames 1 in the time domain. It can be seen that the update periodof the present satellite's basic navigation information is 30 seconds(each sub-frame 1 is 1 page, therefore 10 pages are 10 sub-frames 1, andthe update period of 1 sub-frame 1 is 3 seconds, so the update period ofa group of pages of sub-frame 1 is 3 seconds*10=30 seconds). Completingone transmission of the integrity and differential information of theBeidou system requires a group of pages of sub-frames 2˜4 to broadcast,in which a group of pages of sub-frames 2˜4 consists of 6 pages (thatis, transmitted in a time division manner) respectively, that is, onetransmission of the integrity and differential information of the Beidousystem is completed by 6 consecutive sub-frames 2˜4 in the time domainrespectively. It can be seen that the update period of the integrity anddifferential information of the Beidou system is 18 seconds (each ofsub-frames 2˜4 is 1 page respectively, therefore 6 pages are 6sub-frames 2˜4 respectively, and the update period of a group of pagesof sub-frames 2˜4 is 3 seconds*6=18 seconds). A group of pages ofsub-frame 5 consists of 120 pages (that is, transmitted in a timedivision manner), that is, one transmission of all the satellitealmanacs, the ionosphere information and the time synchronizationinformation with other systems is completed by continuous 120 sub-frames5 in the time domain. It can be seen that the update period of all thesatellite almanacs, the ionosphere information and the timesynchronization information with other systems is 6 minutes (eachsub-frame 5 is 1 page, therefore 120 pages are 120 sub-frames 5, and theupdate period of a group of pages of sub-frame 5 is 3 seconds*120=360seconds=6 minutes).

A page reflects the sequential changes of each sub-frame in the timedomain. In order for easier understanding of the concept of a page,refer to FIG. 7. FIG. 7 is a schematic diagram illustrating anarrangement relationship in time of pages of a sub-frame in a navigationmessage frame structure model according to an embodiment of the presentinvention. As shown in FIG. 7, along a time axis T, main frames eachincluding 5 sub-frames are sequentially broadcast. That is to say, aftersub-frame 1, sub-frame 2, sub-frame 3, sub-frame 4 and sub-frame 5 ofthe first main frame are broadcast in sequence, the followed issub-frame 1, sub-frame 2, sub-frame 3, sub-frame 4 and sub-frame 5 ofthe second main frame, and so on. It can be seen that the repetitionperiod of the same sub-frame is equivalent to the length of one mainframe, that is, 3 seconds.

In FIG. 7, taking sub-frame 2 as an example, sub-frame 2 of the firstmain frame is page 1 of sub-frame 2, sub-frame 2 of the second mainframe is page 2 of sub-frame 2, sub-frame 2 of the third main frame ispage 3 of sub-frame 2, sub-frame 2 of the fourth main frame is page 4 ofsub-frame 2, sub-frame 2 of the fifth main frame is page 5 of sub-frame2, and sub-frame 2 of the sixth main frame is page 6 of sub-frame 2.That is to say, sub-frames 2 of the six main frames consecutive in timeconstitute 6 pages of sub-frame 2, and the message information broadcastby these 6 pages (that is, 6 sub-frames 2) is different between eachother. Therefore, the broadcast frequency (that is, update frequency) ofthe message information broadcast by the 6 pages of sub-frame 2 is 18seconds. Similarly, sub-frames 2 of the seventh to twelfth main framesmay constitute 6 pages of the next group (that is, the next updateperiod) of sub-frame 2 for broadcasting the updated message information.

In the navigation message frame structure model as described above, inaddition to information bits for broadcasting the present satellite'sbasic navigation information, all the satellite almanacs, the timesynchronization information with other systems, the integrity anddifferential information of the Beidou system and the ionosphereinformation, unused information bits are usually reserved. Specifically,in the navigation message frame structure model shown in FIG. 5, thelower 150 bits of pages 1˜10 of sub-frame 1, pages 1˜6 of sub-frame 4and pages 14˜34, pages 74˜94, pages 103˜120 of sub-frame 5 are reservedinformation bits. In addition, it can be known according to the usagecase of the navigation message link resource that, currently, the lower120 bits of sub-frame 3, sub-frame 4 and pages 117˜120 of sub-frame 5are reserved information bits (that is, free resource bits). Therefore,satellite-level enhanced parameters can be further broadcast by usingthese reserved information bits.

Considering the page setting of each sub-frame shown in FIG. 5 and thecase of reserved information bits of each sub-frame as described abovesynthetically, the message information broadcast by sub-frame 3 andsub-frame 4 can implement an update period of 3 seconds and an integralmultiple thereof while the message information broadcast by sub-frame 5may implement an update period of 6 minutes. Therefore, the processor401 may determine into which reserved information bit in which page ofwhich sub-frame the enhanced parameter is inserted to be broadcastaccording to the byte size and the broadcast frequency of the enhancedparameter (e.g., a satellite-based enhanced parameter) that needs to bebroadcast. For example, according to the use requirement of thesatellite clock difference correction, its update period is 18 seconds.Therefore, the satellite clock difference correction can be insertedinto reserved information bits of sub-frame 2/3 to be broadcast, so asto achieve the broadcast frequency of 18 seconds. The update period ofthe satellite orbit correction is 6 minutes, thus it can be insertedinto reserved information bits of sub-frame 5 to be broadcast, so as toachieve the broadcast frequency of 6 minutes.

After the processor 401 completes the message arrangement of theenhanced parameter, the transmitter 402 may upload the arranged messageto a broadcast satellite (e.g., the I-branch of the GEO satellite) forbroadcasting the message. Thereby, a user terminal can receive thebroadcast message, thus obtain the enhanced parameter so as to correctthe error in the basic navigation information to improve the navigationaccuracy.

It should be noted that although the navigation message frame structuremodel given in FIG. 5 and FIG. 6 takes the Beidou system as an example,the present invention is not limited thereto, and those skilled in theart can employ the navigation message frame structure model of any othersuitable navigation system.

In the message broadcast apparatus 40 for the enhanced parameter in thesatellite navigation system according to the embodiment of the presentinvention, by making the basic navigation information and enhancedinformation be uniformly broadcast, the scalability of the navigationmessage is improved, the satellite-and-earth-integrated flexiblebroadcast of the navigation message is realized, the flexibility ofmessage broadcasting is improved, the user performance is improved, andthe utilization of channel link resources is improved.

Optionally, in the above message broadcast apparatus 40 for the enhancedparameter in the satellite navigation system, the processor 401 maydetermine the byte size and the broadcast frequency of the enhancedparameter according to a quantization range and a quantization accuracyof the enhanced parameter respectively.

Specifically, the accuracy of basic navigation satellite broadcastephemeris is usually better than 10 meters. The URE (User Range Error)increases when orbit maneuvers. When the URE is greater than a certainnumerical value, this satellite may be regarded as being unavailable inthe short term, and the orbital radial error is classified as a clockdifference. For this reason, the range of an orbit correction may be setas a range of 3 times, that is, ±30 meters can meet the requirements.Taking into account further abnormal cases, this range can beappropriately enlarged, for example, the typical value is set to ±64meters. Taking into account the need for decimeter-level wide-areadifferential accuracy, the quantization accuracy of this parameter canbe designed on the centime ters-level.

The existing clock difference can represent ±409 meters with aquantization error of 0.1 meters. In order to improve the accuracy ofthe clock difference correction, the clock difference correction residueis increased, and the range of the residue is ±0.0625 meters. Takinginto account the need for decimeter-level wide-area differentialaccuracy, the quantization accuracy can be designed on the centimeters-level.

The partition correction is made on the basis of the correction of theclock difference. The calculation of the highest accuracy of positioningneeds using such correction. The accuracy of the resolving and theparameter fitting of the clock difference is usually better than 1nanosecond, and the accuracy of the orbit correction is also better than2 nanoseconds. Therefore, the range of the partition correction is setat ±5 nanoseconds so as to satisfy the representation requirement of theparameter. This range can be set as ±8 nanoseconds in consideration offurther abnormal cases. Other cases beyond the representation range willbe uniformly classified into the clock difference parameter. Taking intoaccount the requirement of high accuracy, the quantization unit of thisparameter can be 0.0625 nanoseconds, and the truncation error at thistime is 1 cm.

Ionosphere correction parameters use models including, but being notlimited to, grid ionosphere models, 8-parameter models, or 14-parametermodels, and preferably use grid ionosphere models. The accuracy of theresolving of the grid ionosphere is about 0.5 meters and thequantization accuracy of too high is a waste for resources. The designfor the quantization accuracy of 0.1 meter can meet the requirement. Themaximum delay is generally no more than 50 meters, and larger delays canbe marked as unavailable. Therefore, the value of this parameter can bedesigned in the range of tens of meters, with a typical value being 63meters.

According to the above design considerations for the quantization rangeand the quantization accuracy of each enhanced parameter, the byte sizeand the update period of each enhanced parameter may be determined. Forexample, the update period of the satellite clock difference correctionparameters is preferably 18 seconds, the update period of the satelliteorbit correction parameters is preferably 6 minutes, the update periodof the partition comprehensive correction parameters is preferably 36seconds, and the update period of the ionosphere correction parameter ispreferably 3 minutes. As another example, each partition comprehensivecorrection occupies 8 bits of information bits, and each satellite'ssatellite orbit correction occupies 40 bits of information bits, and soon. As described above, the message arrangement scheme of each enhancedparameter in the navigation message frame structure model may bedetermined according to the byte size and update period of each enhancedparameter.

Optionally, in the above message broadcast apparatus 40 for the enhancedparameter in the satellite navigation system, the enhanced parameter mayinclude satellite clock difference correction parameters and partitioncomprehensive correction parameters, and the processor 401 may insertthe satellite clock difference correction parameters into a first groupof predetermined positions in the reserved space of sub-frame 2 andsub-frame 3 and transmits the satellite clock difference correctionparameters by 6 pages in a time division manner (that is, one broadcastof the satellite clock difference correction parameters is completed by6 pages), and insert the partition comprehensive correction parametersinto a second group of predetermined positions in the reserved space ofsub-frame 2 to sub-frame 4 and transmits the partition comprehensivecorrection parameters by the 12 pages in a time division manner (thatis, one broadcast of the partition comprehensive correction parametersis completed by 12 pages in sub-frame 2 to sub-frame 4 respectively).

Specifically, as described above, the update period of the satelliteclock difference correction is 18 seconds. As shown in FIG. 5, theupdate period of the integrity and differential information of theBeidou system broadcast by sub-frames 2˜4 via 6 pages is also 18seconds. Therefore, the satellite clock difference correction parametersmay be inserted into certain information bits in the reserved space insub-frames 2˜4 to achieve the update period of 18 seconds. Here, itshould be understood that choosing to insert the satellite clockdifference correction parameters into the first group of predeterminedpositions in the reserved space of sub-frame 2 and sub-frame 3 is onlyas an example, and the present invention is not limited thereto. Thoseskilled in the art may select other suitable reserved information bitsaccording to the teachings of the present invention.

As described above, the update period of the partition comprehensivecorrection is 36 seconds. Although, as shown in FIG. 5, the updateperiod of the integrity and differential information of the Beidousystem broadcast by sub-frames 2˜4 via 6 pages is 18 seconds, if twogroups of 6 pages (i.e., 12 pages) of sub-frames 2˜4 are used tobroadcast, an update period of 36 seconds can also be achieved. Forexample, taking FIG. 7 as an example, the partition comprehensivecorrection parameters may be broadcast through certain information bitsin the reserved space of sub-frames 2˜4 in the first to twelfth mainframes, and thereby one broadcast of the partition comprehensivecorrection parameters may be achieved.

It should be understood that the first group of predetermined positionsand the second group of predetermined positions described herein is inorder for distinguishing a set of reserved information bits forbroadcasting the satellite clock difference correction parameters from aset of reserved information bits for broadcasting the partitioncomprehensive correction parameters. However, it is possible that a partof the positions in the first group of predetermined positions coincidewith a part of positions in the second group of predetermined positions,that is, the broadcasting of the satellite clock difference correctionparameters and the broadcasting of the partition comprehensivecorrection parameters may share some reserved information bits. Themessage arrangements of the satellite clock difference correctionparameters and the partition comprehensive correction parameters will befurther described in detail by way of examples hereinafter.

As described above, sub-frames 2˜4 may not be fixed to be composed of 6pages respectively, that is, the update period of the message broadcastmay not be fixed at 18 seconds, but may be implemented as an updateperiod of a multiple of 3 seconds. Therefore, by flexibly arrangingpages of a sub-frame, the dynamic adjustment, the flexible allocationand the combination of the rapid and slow update frequencies of themessage arrangement are realized, thereby saving resources.

Optionally, in the above message broadcast apparatus 40 for the enhancedparameter in the satellite navigation system, the enhanced parameterincludes partition comprehensive correction parameters, and thepartition comprehensive correction parameters include partitioncomprehensive corrections, area identifiers and satellite identifiers.Additionally, the area identifiers are used for, for each of areas inthe satellite navigation system, employing a 1-bit information bitrespectively to identify whether there is a partition comprehensivecorrection that needs to be broadcast, and the processor 401 inserts thearea identifiers into a third group of predetermined positions in thereserved space of page 1 of sub-frame 2. Additionally, the satelliteidentifiers are used for, for each of satellites in the satellitenavigation system, employing a 1-bit information bit respectively toidentify whether there is a partition comprehensive correction thatneeds to be broadcast, and the processor 401 inserts the satelliteidentifiers into a fourth group of predetermined positions in thereserved space of page 2 to page 4 of sub-frame 2. Additionally, theprocessor 401 inserts partition comprehensive corrections, whichcorrespond to different areas and different satellites respectively andneeds to be broadcast, into a fifth group of predetermined positions inthe reserved space of page 1 to page 6 of sub-frame 3 and sub-frame 4sequentially. Wherein. the broadcast period of the partitioncomprehensive correction parameters is 30 seconds to 3 minutes, andpreferably 36 seconds. The embodiment of the present invention takes 36seconds as an example, but is merely an example, not a limitation.

Specifically, the satellite navigation system can be divided intomultiple areas, and each of areas broadcasts one partition comprehensivecorrection. Limited by satellite downlink navigation signal linkresources, different satellites may broadcast different partitioncomprehensive corrections. Here, for the sake of easily understanding,the Beidou satellite navigation system is still taken as an example forillustration by way of examples. In the Beidou satellite navigationsystem, for example, if the system is divided into 30 areas, there are atotal of 63 satellites. Therefore, for combinations of different areasand different satellites, there may be a total of 30×63=1890 partitioncomprehensive corrections. However, usually only a part of the areas anda part of satellites need to broadcast the corresponding partitioncomprehensive corrections. Therefore, if information bits are allocatedfor all possible partition comprehensive corrections for broadcastingthem, excessive channel link resources will be occupied, resulting in awaste of resources.

In order to save resources, the present invention dynamically adjuststhe information resource mode and broadcasts partition comprehensivecorrections by employing a shared identification bit. In order tofacilitate understanding of the specific message arrangement manner ofthe present invention, a detailed description will be made inconjunction with FIGS. 8A to 8L below. FIGS. 8A to 8L are schematicdiagrams respectively illustrating examples of message arrangements ofpages 1˜6 of sub-frames 2˜4 for broadcasting partition comprehensivecorrection parameters according to an embodiment of the presentinvention. As shown on the far left of each figure, a sub-frame numberand page number i are shown. The numbers above the information bitsequence indicate the bit numbers of the corresponding information bitsin the page, MSB represents the most significant bit, and LSB representsthe least significant bit.

Firstly, area identifiers are set to be used for, for each of 30 areas,employing a 1-bit information bit respectively to identify whether thereis a partition comprehensive correction that needs to be broadcast. FIG.8A shows the message arrangement of page 1 of sub-frame 2. As shown inFIG. 8A, the 134th bit is used to broadcast the area identifier AREAI1of area 1, and when this identification bit is “1”, it indicates thatthere is a partition comprehensive correction that needs to be broadcastin area 1, and when this identification bit is “0”, it indicates thatthere is no partition comprehensive correction that needs to bebroadcast in area 1. Similarly, although not shown in FIG. 8A, the 135thbit is used to broadcast the area identifier AREAI2 of area 2, and whenthis identification bit is “1”, it indicates that there is a partitioncomprehensive correction that needs to be broadcast in area 2, and whenthis identification bit is “0”, it indicates that there is no partitioncomprehensive correction that needs to be broadcast in area 2, and soon. Finally, the 171th bit is used to broadcast the area identifierAREAI30 of area 30, and when this identification bit is “1”, itindicates that there is a partition comprehensive correction that needsto be broadcast in area 30, and when this identification bit is “0”, itindicates that there is no partition comprehensive correction that needsto be broadcast in area 30. It should be noted that “P” in the figurerepresents 8 bits of check bits. It can be understood that, here, the134th bit to the 142th bit and the 151th bit to the 170th bit maycorrespond to the third group of predetermined positions as describedabove, for broadcasting the area identifiers AREI1 to AREI30 of 30areas.

Secondly, satellite identifiers are set to be used for, for each of the63 satellites, employing a 1-bit information bit respectively toidentify whether there is a partition comprehensive correction thatneeds to be broadcast. FIGS. 8B to 8D show the message arrangements ofpages 2˜4 of the sub-frame 2 respectively. As shown in FIG. 8B, the134th bit in page 2 of sub-frame 2 is used to broadcast the satelliteidentifier BDID1 of satellite 1, and when this identification bit is“1”, it indicates that there is a partition comprehensive correctionthat needs to be broadcast for satellite 1, and when this identificationbit is “0”, it indicates that there is no partition comprehensivecorrection that needs to be broadcast for satellite 1. Similarly,although not shown in FIG. 8B, the 135th bit is used to broadcast thearea identifier BDID2 of satellite 2, and when this identification bitis “1”, it indicates that there is a partition comprehensive correctionthat needs to be broadcast for satellite 2, and when this identificationbit is “0”, it indicates that there is no partition comprehensivecorrection that needs to be broadcast for satellite 2, and so on.Finally, the 171st bit is used to broadcast the satellite identifierBDID30 of satellite 30, and when this identification bit is “1”, itindicates that there is a partition comprehensive correction that needsto be broadcast for satellite 30, and when this identification bit is“0”, it indicates that there is no partition comprehensive correctionthat needs to be broadcast for satellite 30. As mentioned before, “P” inthe figure represents 8 bits of check bits. It can be understood that,here, the 134th bit to the 142th bit and the 151th bit to the 170th bitare used to broadcast the satellite identifiers BDID1 to BDID30 of the30 satellites of satellites 1˜30.

FIG. 8C shows the message arrangement of page 3 of sub-frame 2. As shownin FIG. 8C, the 134th bit to the 142th bit and the 151th bit to the170th bit of page 3 of sub-frame 2 are used to broadcast the satelliteidentifiers BDID31 to BDID60 of the 30 satellites of satellites 31˜60,details thereof is similar with those of FIG. 8B and will no longer bedescribed here. FIG. 8D shows the message arrangement of page 4 ofsub-frame 2. As shown in FIG. 8D, the 134th bit to 136th bit of page 4of sub-frame 2 are used to broadcast the satellite identifiers BDID61 toBDID63 of the three satellites of satellites 61˜63. The 137th bit to the142th bit and the 151th bit to the 170th bit can be used to broadcastother information or remain reserved. It can be understood that, here,the 134th bits to the 142th bits and the 151th bits to the 170th bits ofpages 2-3 of sub-frame 2 and the 134th bit to the 136th bit of page 4 ofsub-frame 2 may correspond to the fourth group of predeterminedpositions as described above, for broadcasting the satellite identifiersBDID1 to BDID63 of 63 satellites.

FIG. 8E shows the message arrangements of pages 5˜6 of sub-frame 2. Asshown in FIG. 8E, the 134th bits to the 142th bits and the 151th bits tothe 170th bits of pages 5˜6 of sub-frame 2 are still reserved (asindicated by Rev) for future use.

Finally, partition comprehensive corrections, which correspond todifferent areas and different satellites respectively and needs to bebroadcast, are inserted into a fifth group of predetermined positions inthe reserved space of page 1 to page 6 of sub-frame 3 and sub-frame 4sequentially. Specifically, FIG. 8F to FIG. 8K respectively show themessage arrangements of pages 1˜6 of sub-frame 3. As shown in FIG. 8F,each partition comprehensive correction occupies 8 bits of informationbits, and the 257th to 262th bits of page 1 of sub-frame 3 are used tobroadcast the upper 6 bits of the first partition comprehensivecorrection (ΔT₁), while the 271th bit to the 272th bit of page 1 ofsub-frame 3 are used to broadcast the lower 2 bits of the firstpartition comprehensive correction (ΔT₁). The 273th bit to the 280th bitof page 1 of sub-frame 3 are used to broadcast the second partitioncomprehensive correction (ΔT₂), the 281th bit to the 288th bit of page 1of sub-frame 3 are used to broadcast the third partition comprehensivecorrection (ΔT₃), and the 289th bit to the 292th bit of page 1 ofsub-frame 3 are used to broadcast the upper 4 bits of the fourthpartition comprehensive correction (ΔT₄). It can be seen that 3.5partition comprehensive corrections can be broadcast through the 28information bits of the 257th bit to the 262th bit and the 271th bit tothe 292th bit of page 1 of sub-frame 3.

Similarly, as shown in FIG. 8G to FIG. 8K, each page of pages 2˜6 ofsub-frame 3 may broadcast 3.5 the partition comprehensive correctionsrespectively by employing the 28 information bits of the 257th bit tothe 262th bit and the 271th bit to the 292th bit. The details thereofare similar with those of FIG. 8F and thus will no longer be describedhere.

FIG. 8L shows the message arrangement of pages 1˜6 of sub-frame 4. Asshown in FIG. 8L, the 44th bit to the 47th bit are used to broadcast thelower 4 bits of the last partition comprehensive correction broadcast bythe preceding sub-frame 3. For example, the 44th bit to the 47th bit ofpage 1 of sub-frame 4 are used to broadcast the lower 4 bits of thefourth partition comprehensive correction (ΔT₄). The 48th bits to the52th bits, the 61th bits to the 82th bits, the 91th bits to the 142thbits and the 151th bits to the 167th bits of pages 1˜6 of sub-frame 4are used to broadcast 11 partition comprehensive corrections. That is tosay, each of pages 1˜6 of sub-frame 4 can broadcast 11.5 partitioncomprehensive corrections. Therefore, a total of 90 partitioncomprehensive corrections can be broadcast by pages 1˜6 of sub-frame 3and sub-frame 4, and a total of 180 partition comprehensive correctionscan be broadcast by two groups of pages 1˜6.

It can be understood that, here, the 257th bits to the 262th bits andthe 271th bits to the 292th bits of pages 1˜6 of sub-frame 3 and the48th bits to the 52th bits, the 61th bits to the 82th bits, the 91thbits to the 142th bits and the 151th bits to the 167th bits of pages 1˜6of sub-frame 4 may correspond to the fifth group of predeterminedpositions as described above, for sequentially broadcasting the existingpartition comprehensive corrections.

It should be noted that since the update period of the partitioncomprehensive correction parameters is 36 seconds, that is, updating isperformed once every 12 pages. Specifically, in the time domain, forexample, in the first period of 36 seconds, the number of partitioncomprehensive corrections that need to be broadcast by sub-frames 3 andsub-frames 4 in the first to twelfth main frames and which area andwhich satellite each of the partition comprehensive correctionscorresponds to are determined according to the area identifiers and thesatellite identifiers broadcast in sub-frames 2 in the first to sixthmain frames in the time domain. Similarly, in the second period of 36seconds, the number of partition comprehensive corrections that need tobe broadcast by sub-frames 3 and sub-frames 4 in the 13th to 24th mainframes and which area and which satellite each of the partitioncomprehensive corrections corresponds to are determined according to theupdated area identifiers and the updated satellite identifiers broadcastin sub-frames 2 in the 13th to 18th main frames in the time domain, andso on.

It should be understood that although at most 180 partitioncomprehensive corrections can be broadcast as described above, if only100 partition comprehensive corrections for example need to be broadcastin a certain period of 36 seconds, remaining information bits, after the100 partition comprehensive corrections are sequentially broadcast, inthe fifth group of predetermined positions of sub-frame 3 and sub-frame4 may be empty or as reserved bits.

Since the area identifiers and the satellite identifiers are used toidentify which areas and which satellites have partition comprehensivecorrections that need to be broadcast as described above, the fifthgroup of predetermined positions in sub-frame 3 and sub-frame 4 can beused only for broadcasting the partition comprehensive corrections thatneed to be broadcast without allocating fixed information bits forpartition comprehensive corrections that do not need to be broadcast,thus saving channel link resources. Moreover, after each of updateperiods, since the area identifiers and the satellite identifiers maychange, partition comprehensive corrections that need to be broadcastwill also change, so the fifth group of predetermined positions ofsub-frame 3 and sub-frame 4 may broadcast the updated partitioncomprehensive corrections corresponding to different areas and differentsatellites. It can be seen that all satellites in the satellitenavigation system can share identification bits and perform dynamicadjustment, thus saving resources and realizing fast uploading.

Further optionally, in the above message broadcast apparatus 40 for theenhanced parameter in the satellite navigation system, an area index iand a satellite index j corresponding to each of the broadcast partitioncomprehensive corrections may be respectively defined as follows:

i=INT(n, x)+1;

j=MOD(n, x).

Wherein n denotes the number of the broadcast partition comprehensivecorrection, and x denotes the total number of satellites that needs tobroadcast partition comprehensive corrections.

Specifically, as described above, partition comprehensive correctionsthat need to be broadcast are sequentially inserted into all pages ofsub-frame 3 and sub-frame 4, that is, the messages of these partitioncomprehensive corrections are sequentially arranged. For example, thevalue of n corresponding to the first partition comprehensive correction(ΔT₁) broadcast in page 1 of sub-frame 3 is “1”, the value of ncorresponding to the second partition comprehensive correction (ΔT₂)broadcast in page 1 of sub-frame 3 is“2” . . . . The value of ncorresponding to the first partition comprehensive correction broadcastin page 1 of sub-frame 4 is “4”, the value of n corresponding to thesecond partition comprehensive correction broadcast in page 1 ofsub-frame 4 is “5”, and so on.

As mentioned before, although there are a total of 63 satellites, notevery satellite has a partition comprehensive correction that needs tobe broadcast. For example, it is assumed that x=10, that is, when thetotal number of satellites broadcasting the partition comprehensivecorrections is 10, for the first partition comprehensive correction ΔT₇₆in page 6 of sub-frame 3, n=76, so its corresponding area indexi=INT(76, 10)+1=8, and its corresponding satellite index j=MOD (76,10)=6. That is to say, the partition comprehensive correction ΔT₇₆corresponds to area 8 and satellite 6.

Through the above formula, specific area and satellite corresponding toeach of the broadcast partition comprehensive corrections may bederived. Therefore, by combining area identifiers, satellite identifiersand partition comprehensive corrections, it is possible to achieve theaccurate broadcast of the partition comprehensive corrections and tosave resources.

Optionally, in the above message broadcast apparatus 40 for the enhancedparameter in the satellite navigation system, the enhanced parameterincludes satellite clock difference correction parameters, and thesatellite clock difference correction parameters include satelliteidentifiers and satellite clock difference correction residues.Additionally, the satellite identifiers are used for, for each ofsatellites in the satellite navigation system, employing a 1-bitinformation bit respectively to identify whether there is a satelliteclock difference correction residue that needs to be broadcast, and theprocessor 401 inserts the satellite identifiers into a third group ofpredetermined positions in the reserved space of page 1 of sub-frame 2.Additionally, the processor 401 inserts the satellite clock differencecorrection residues, which correspond to different satellitesrespectively and need to be broadcast, into a sixth group ofpredetermined positions in the reserved space of page 5 and page 6 ofsub-frame 4 sequentially. Additionally, the broadcast period of thesatellite clock difference correction parameters is 18 seconds to 2minutes, and preferably 18 seconds. The 18 seconds of the embodiment ofthe present invention is merely an example, not a limitation.

Specifically, for convenience of explanation, the Beidou satellitenavigation system is still taken as an example. As mentioned before, theBeidou satellite navigation system has a total of 63 satellites.However, similar to the aforementioned partition comprehensivecorrections, not every satellite has a satellite clock differencecorrection residue that needs to be broadcast. Therefore, it is alsopossible to set satellite identifiers for employing, for each of 63satellites, a 1-bit information bit respectively to identify whetherthere is a satellite clock difference correction residue that needs tobe broadcast. For the satellite identifier of each satellite, when thisidentification bit is “1”, it indicates that there is a satellite clockdifference correction residue that needs to be broadcast forth issatellite, and when this identification bit is “0”, it indicates thatthere is no satellite clock difference correction residue that needs tobe broadcast forth is satellite.

Here, the satellite identifiers used for the satellite clock differencecorrection residues are different from the satellite identifiers usedfor the partition comprehensive corrections, but their effects aresimilar with each other and will no longer be described here.

Each of satellite clock difference correction residues consists of 4bits of information bits. Usually, each GEO satellite can broadcastsatellite clock difference correction residues of 18 satellites. FIGS.9A to 9B are schematic diagrams respectively illustrating examples ofmessage arrangements of pages 5˜6 of sub-frame 3 for broadcastingsatellite clock difference correction parameters according to anembodiment of the present invention. As shown on the far left of eachfigure, a sub-frame number and page number i are shown. Numbers abovethe information bit sequence indicates the bit numbers of thecorresponding information bits in the page, MSB represents the mostsignificant bit, and LSB represents the least significant bit. As shownin FIG. 9A, information bits different from those broadcasting partitioncomprehensive corrections in page 5 of sub-frame 3 broadcast satelliteclock difference correction residues of the frequency point B1 of the 18satellites, as shown by Δt_(res1), Δt_(res2) . . . Δt_(res18).Similarly, as shown in FIG. 9B, information bits different from thosebroadcasting partition comprehensive corrections in page 6 of sub-frame3 broadcast satellite clock difference correction residues of the B2frequency point of the 18 satellites, as shown by Δt_(res1), Δt_(res2) .. . Δt_(res18).

It should be understood that if the total number of satellites thatthere are satellite clock difference correction residues that need to bebroadcast is less than 18, some information bits in the predeterminedpositions for broadcasting satellite clock difference correctionresidues shown in FIG. 9A and FIG. 9B may be empty or as reservedinformation bits.

As described above, the update period of the satellite clock differencecorrection residues is 18 seconds while the update period of thepartition comprehensive corrections is 36 seconds. With flexible messagearrangement, it is possible to realize the rapid-slow combination ofdifferent broadcast frequencies between the satellite clock differencecorrection residues and the partition comprehensive corrections.

Further optionally, in the above message broadcast apparatus 40 for theenhanced parameter in the satellite navigation system, the processor 401inserts a broadcast information category identifier into a predetermined1-bit information bit in the reserved space of page 4 of sub-frame 2,and the satellite clock difference correction residues are broadcast inthe sixth group of predetermined positions when the broadcastinformation category identifier is one of 1 and 0, and GPS satellitedifferential fast change information is broadcast in the sixth group ofpredetermined positions when the broadcast information categoryidentifier is the other of 1 and 0.

Specifically, still referring to FIG. 8D, after BDID63, a 1-bitinformation bit may be used to broadcast the information categoryidentifier, as shown by GPS flag. For example, when this identificationbit GPS flag is “1”, it indicates that the sixth group of predeterminedpositions as described above is used to broadcast satellite clockdifference correction residues, and the message arrangement is as shownin FIGS. 9A and 9B. When this identification bit GPS flag is “0”, itindicates that the sixth group of predetermined positions as describedabove is used to broadcast the GPS satellite differential fast changeinformation, as shown in FIGS. 8J and 8K. Specifically, RUAIi1˜RUAIi3and Δt_(GPSi1)˜Δt_(GPSi3) in FIGS. 8J and 8K represent the GPS satellitedifferential fast change information.

It should be understood that, obviously, the meanings of “1” and “0” ofthe identification bit GPS flag are not limited to the above-describedexemplary case, but may be interchanged.

By setting the information category identifier, resource sharing betweendifferent satellite navigation systems can be realized, channel linkresources are saved, and the message arrangement can be flexibly anddynamically adjusted.

Optionally, in the above message broadcast apparatus 40 for the enhancedparameter in the satellite navigation system, the enhanced parameterincludes GPS partition comprehensive correction parameters, and the GPSpartition comprehensive correction parameters include GPS partitioncomprehensive corrections, GPS area identifiers and GPS satelliteidentifiers. Additionally, the GPS area identifiers are used for, foreach of GPS areas, employing a 1-bit information bit respectively toidentify whether there is a GPS partition comprehensive correction thatneeds to be broadcast, and the processor 401 inserts the GPS areaidentifiers into a seventh group of predetermined positions in thereserved space of page 23 and page 83 of sub-frame 5. Additionally, theGPS satellite identifiers are used for, for each of GPS satellites,employing a 1-bit information bit respectively to identify whether thereis a GPS partition comprehensive correction that needs to be broadcast,and the processor 401 inserts the GPS satellite identifiers into aneighth group of predetermined positions in the reserved space of page 23and page 83 of sub-frame 5. Additionally, the processor 401 inserts theGPS partition comprehensive corrections, which correspond to differentGPS areas and different GPS satellites respectively and need to bebroadcast, into a ninth group of predetermined positions in the reservedspace of page 23 to page 30 and page 83 to page 90 of sub-frame 5sequentially. Additionally, the broadcast period of the GPS partitioncomprehensive correction parameters is 30 seconds to 3 minutes, andpreferably 36 seconds. The 36 seconds mentioned in the embodiment of thepresent invention is merely an example, not a limitation.

Specifically, although the current GPS satellite navigation system arenot divided by regions like the Beidou system, in practice, regionaldivision may be conducted on the GPS satellite navigation system and theGPS partition comprehensive corrections may be further applied. FIGS.10A to 10E are schematic diagrams respectively illustrating examples ofmessage arrangements of pages 23˜30, 83˜90 of sub-frame 5 forbroadcasting GPS partition comprehensive correction parameters accordingto an embodiment of the present invention. As shown on the far left ofeach figure, a sub-frame number and page number i are shown. Numbersabove the information bit sequence indicate the bit numbers of thecorresponding information bits in the page, MSB represents the mostsignificant bit, and LSB represents the least significant bit.

Similarly with the aforementioned partition comprehensive correctionsfor the Beidou system, for example, the GPS satellite navigation systemis divided into 30 GPS areas, and each of GPS areas broadcasts one GPSpartition comprehensive correction. Correspondingly, the GPS areaidentifiers are set for employing, for each of 30 GPS areas, a 1-bitinformation bit respectively to identify whether there is a GPSpartition comprehensive correction that needs to be broadcast. FIG. 10Ashows the message arrangement of pages 23, 83 of sub-frame 5. As shownin FIG. 10A, AREAI1, AREAI2, AREAI30 respectively represent the GPS areaidentifiers of the 30 GPS areas. When a certain identification bit is“1”, it indicates that there is a GPS partition comprehensive correctionthat needs to be broadcast for the GPS area identified by it, and whenthis identification bit is “0”, it indicates that there is no GPSpartition comprehensive correction that needs to be broadcast for theGPS area identified by it. It can be understood that, here, the 30 bitsof information bits for broadcasting the GPS area identifiers AREI1 toAREI30 of the 30 GPS areas in pages 23, 83 of sub-frame 5 may correspondto the seventh group of predetermined positions as described above.

Unlike the Beidou satellite navigation system, the GPS satellitenavigation system has a total of 36 GPS satellites. The GPS satelliteidentifiers are set for employing, for each of 36 GPS satellites, a1-bit information bit respectively to identify whether there is a GPSpartition comprehensive correction that needs to be broadcast. As shownin FIG. 10A, GPS1, GPS2, . . . , GPS36 respectively indicate the GPSsatellite identifiers of the 36 GPS satellites. When a certainidentification bit is “1”, it indicates that there is a GPS partitioncomprehensive correction that needs to be broadcast for the GPSsatellite identified by it, and when this identification bit is “0”, itindicates that there is no GPS partition comprehensive correction thatneeds to be broadcast for the GPS satellite identified by it. It can beunderstood that, here, the 36 bits of information bits for broadcastingthe GPS satellite identifiers GPS1 to GPS36 of the 36 GPS satellites inpages 23, 83 of sub-frame 5 may correspond to the eighth group ofpredetermined positions as described above.

The GPS partition comprehensive corrections, which correspond todifferent GPS areas and different GPS satellites respectively and needto be broadcast, are inserted into a ninth group of predeterminedpositions in the reserved space of pages 23˜30, 83˜90 of sub-frame 5sequentially. Specifically, similarly with the Beidou system, each GPSpartition comprehensive correction is composed of 8 bits. Referring toFIG. 10A, the 228th bits to the 232th bits, the 241th bits to the 262thbits and the 271th bits to the 291th bits of pages 23, 83 of sub-frame 5are used to broadcast 6 GPS partition comprehensive corrections, asshown by ΔTG₁ to ΔTG₆. FIG. 10B shows the message arrangement of pages24˜29 of sub-frame 5. As shown by ΔTG_(a1) to ΔTG_(a22), 22 GPSpartition comprehensive corrections can be broadcast per page. FIG. 10Cshows the message arrangement of pages 84˜89 of sub-frame 5. Similarlywith FIG. 10B, as shown by ΔTG_(a1) to ΔTG_(a22), 22 GPS partitioncomprehensive corrections can be broadcast per page. FIGS. 10D and 10Eshow the message arrangements of page 30 and page 90 of sub-frame 5,respectively. As shown by ΔTG_(a1) to ΔTG_(a13) in FIGS. 10D and 10E,each of page 30 and page 90 can broadcast 13 GPS partition comprehensivecorrections. Therefore, a total of 151 GPS partition comprehensivecorrections can be broadcast by pages 23˜30 of sub-frame 5, andsimilarly, a total of 151 GPS partition comprehensive corrections can bebroadcast by pages 83˜90 of sub-frame 5.

As described above in conjunction with FIG. 5, sub-frame 5 in thenavigation message frame structure model is composed of 120 pages, andcan achieve the broadcast frequency of 6 minutes. Here, since pages23˜30 differ from pages 83˜90 by 60 pages, the update period of the GPSpartition comprehensive corrections can be implemented as 3 minutes.That is to say, based on the GPS area identifiers and the GPS satelliteidentifiers in page 23 of sub-frame 5, the corresponding GPS partitioncomprehensive corrections can be broadcast in pages 23˜30; the GPS areaidentifiers and the GPS satellite identifiers broadcast in page 83 ofsub-frame 5 may be different from those in page 23, that is, the GPSarea identifiers and the GPS satellite identifiers are updated after 3minutes, therefore, the GPS partition comprehensive correctionsbroadcast in pages 83˜90 of sub-frame 5 are based on the GPS areaidentifiers and the GPS satellite identifiers broadcast in page 83 ofsub-frame 5.

The GPS area index and the GPS satellite index corresponding to each GPSpartition comprehensive correction may be determined similarly with theforegoing partition comprehensive correction for the Beidou system, andwill no longer be described here.

It should be understood that although at most 151 GPS partitioncomprehensive corrections can be broadcast every 3-minute period asdescribed above, if only 100 GPS partition comprehensive correctionsneed to be broadcast in a certain 3-minute period, remaining informationbits, after the 100 partition comprehensive corrections are sequentiallybroadcast, in the ninth group of predetermined positions of sub-frame 5may be empty or as reserved bits.

Since the GPS area identifiers and the GPS satellite identifiers areused to identify which GPS areas and which GPS satellites have GPSpartition comprehensive corrections that need to be broadcast asdescribed above, the ninth group of predetermined positions in sub-frame5 can be used only for broadcasting the GPS partition comprehensivecorrections that need to be broadcast without allocating fixedinformation bits for GPS partition comprehensive corrections that do notneed to be broadcast, thus saving channel link resources. Moreover,after each of update periods, since the GPS area identifiers and the GPSsatellite identifiers may change, GPS partition comprehensivecorrections that need to be broadcast will also change, so the ninthgroup of predetermined positions of sub-frame 5 may broadcast theupdated GPS partition comprehensive corrections corresponding todifferent GPS areas and different GPS satellites. It can be seen thatall GPS satellites in the GPS satellite navigation system can shareidentification bits and perform dynamic adjustment, thus savingresources and realizing fast uploading. In addition, since the broadcastposition of the GPS partition comprehensive correction parameters isdifferent from the broadcast position of the partition comprehensivecorrections for the Beidou system as described above, enhancedparameters of different satellite navigation systems can besimultaneously broadcast at different update frequencies in the samenavigation message frame structure model, and thus the scalability ofthe navigation message is further improved.

Optionally, in the above message broadcast apparatus 40 for the enhancedparameter in the satellite navigation system, the enhanced parameterincludes satellite orbit correction parameters, and the satellite orbitcorrection parameters include satellite identifiers, satellite broadcastephemeris corrections and equivalent distance error status identifiersof satellite ephemeris corrections. Additionally, the satelliteidentifiers are used for, for each of satellites in the satellitenavigation system, employing a 1-bit information bit respectively toidentify whether there are a satellite broadcast ephemeris correctionand an equivalent distance error status identifier of the satelliteephemeris correction that need to be broadcast, and the processor 401inserts the satellite identifiers into a tenth group of predeterminedpositions in the reserved space of page 23 of sub-frame 5. Additionally,the processor 401 inserts the satellite broadcast ephemeris correctionsand the equivalent distance error status identifiers of satelliteephemeris corrections, which correspond to different satellitesrespectively and need to be broadcast, into a eleventh group ofpredetermined positions in the reserved space of page 117 to page 120,page 31 and page 91 of sub-frame 5. Additionally, the broadcast periodof the satellite orbit correction parameters is 3-6 minutes, andpreferably 6 minutes. The embodiment of the present invention take the 6minutes as an example, but it is merely an example, not a limitation.

Specifically, the Beidou satellite navigation system is still taken asan example for illustration by way of examples. As mentioned before, theBeidou satellite navigation system has a total of 63 satellites.However, not every satellite has a satellite broadcast ephemeriscorrection and an equivalent distance error status identifier of thesatellite ephemeris correction that need to be broadcast. Usually, theGEO satellite broadcasts satellite broadcast ephemeris corrections andequivalent distance error status identifiers of the satellite ephemeriscorrections of 18 satellites. As shown in FIG. 10A, the satelliteidentifiers of the Beidou system can be further broadcast in pages 23,83 of sub-frame 5, as shown by BDID1 to BDID63. When a certainidentification bit is “1”, it indicates that there is a satellitebroadcast ephemeris correction and an equivalent distance error statusidentifier of the satellite ephemeris correction that need to bebroadcast for the satellite identified by it, and when thisidentification bit is “0”, it indicates that there is no satellitebroadcast ephemeris correction and equivalent distance error statusidentifier of the satellite ephemeris correction that need to bebroadcast for the satellite identified by it.

Based on respective satellite identifiers broadcast in page 23 ofsub-frame 5, satellite broadcast ephemeris corrections and equivalentdistance error status identifiers of the satellite ephemeris correctionsthat need to be broadcast are sequentially broadcast in pages 117˜120,31, 91 of sub-frame 5. FIGS. 11A to 11E are schematic diagramsrespectively illustrating examples of message arrangements of pages117˜120, 31, 91 of sub-frame 5 for broadcasting satellite orbitcorrection parameters according to an embodiment of the presentinvention. As shown on the far left of each figure, a sub-frame numberand page number i are shown. Numbers above the information bit sequenceindicate the bit numbers of the corresponding information bits in thepage, MSB represents the most significant bit, and LSB represents theleast significant bit.

As shown in FIG. 11A, a group of ΔX, ΔY, ΔZ represents one satellitebroadcast ephemeris correction, and ΔX, ΔY, ΔZ each occupy 12 bits. Page117 of sub-frame 5 can broadcast 4 complete satellite broadcastephemeris corrections and the complete ΔX, ΔY and the upper 10 bits ofΔZ in the 5th satellite broadcast ephemeris correction. As shown in FIG.11B, page 118 of sub-frame 5 can broadcast the lower 2 bits of ΔZ in the5th satellite broadcast ephemeris correction, the 6th to 9th completesatellite broadcast ephemeris corrections, and the complete ΔX, ΔY andthe upper 8 bits of ΔZ in the 10th satellite broadcast ephemeriscorrection. As shown in FIG. 11C, page 119 of sub-frame 5 can broadcastthe lower 4 bits of ΔZ in the 10th satellite broadcast ephemeriscorrection, the 11th to 14th complete satellite broadcast ephemeriscorrections, and the complete ΔX, ΔY and the upper 6 bits of ΔZ in the15th satellite broadcast ephemeris correction. As shown in FIG. 11D,page 120 of sub-frame 5 can broadcast the lower 6 bits of ΔZ in the 15thsatellite broadcast ephemeris correction, the 16th to 18th completesatellite broadcast ephemeris corrections, and equivalent distance errorstatus identifiers of 16 satellite ephemeris corrections (as shown byEPREI1 to EPREI16). As shown in FIG. 11E, page 31 and page 91 ofsub-frame 5 are used to broadcast the equivalent distance error statusidentifiers of the 17th and 18th satellite ephemeris corrections (asshown by EPREI17 and EPREI18). The equivalent distance error statusidentifier of each satellite ephemeris correction occupies 4 bits.

Note that since the update period of the satellite orbit correctionparameters is 6 minutes, EPREI17 and EPREI18 broadcast in page 31 andpage 91 of sub-frame 5 are the same, that is, repeated; in addition,BDID1˜BDID63 in page 83 of sub-frame 5 are not used for satellitebroadcast ephemeris corrections and equivalent distance error statusidentifiers of the satellite ephemeris corrections.

In addition, it should be noted that in addition to the above-mentionedspecific reserved information bits for broadcasting respective enhancedparameters, other information bits that have been used for broadcastingthe basic navigation information currently are shown in FIGS. 8A-1 to11E. Specifically, for example, Pre represents a frame synchronizationcode, FraID represents a sub-frame count, SOW represents asecond-of-week count, EncF2 to EncF5 represent system use bits, Pnum2represents an integrity and differential information page number, SatH2represents integrity and differential autonomic health information,BD2ID1 to BD2ID30 represent BD2 system satellite identifiers, GPSID1 toGPSID30 represent GPS satellite identifiers, UDREI1 to UDREI18 representuser differential distance error indexes, RURAIi1 to RURAIi3 representarea user distance accuracy indexes, Δti1 to Δti3 represent equivalentclock difference corrections, Δt_(GPSi1) to Δt_(GPSi13) and Δt_(ave)represent GPS area user distance accuracy indexes, Pnum represents apage number. Since these already used information bits are well known tothose skilled in the art, they will no longer be described in order toavoid obscuring the inventive points of the present invention.

The message broadcast apparatus 40 for the enhanced parameter in thesatellite navigation system according to embodiments of the presentinvention is described above with reference to FIGS. 4-11E. In themessage broadcast apparatus 40 for the enhanced parameter in thesatellite navigation system, by combining a frame and a data block in anavigation message structure, the satellite-and-earth-integratedflexible broadcast of the navigation message is realized, the basicnavigation information and the enhanced information can be uniformlybroadcast, the scalability of the navigation message is improved, theflexibility of message broadcasting is improved, the user's useperformance is improved, and the utilization of channel link resourcesis improved.

Note that since the ionosphere correction parameters can utilize themessage arrangement of the existing ionosphere correction parameters inthe navigation message frame structure model, it will no longer bedescribed in detail here.

It should be understood that although the description is made above bytaking the Beidou satellite navigation system and the GPS satellitenavigation system as examples, the present invention is not limitedthereto, and those skilled in the art can apply the present invention toany suitable satellite navigation system in accordance with theteachings of the present invention.

In the following, a message broadcast method 120 for an enhancedparameter in a satellite navigation system according to anotherembodiment of the present invention will be described with reference toFIG. 12. FIG. 12 is a flowchart illustrating a message broadcast method120 for an enhanced parameter in a satellite navigation system accordingto an embodiment of the present invention.

As shown in FIG. 12, the message broadcast method 120 for the enhancedparameter in the satellite navigation system begins at step S1201. Atstep S1201, an insertion position of the enhanced parameter in areserved space in a navigation message frame structure model isdetermined according to the byte size and the broadcast frequency of theenhanced parameter that needs to be broadcast, so as to perform themessage arrangement of the enhanced parameter. Next, at step S1201, thearranged message is uploaded by a ground base station to a broadcastsatellite for broadcasting the message. The navigation message framestructure model is defined by a superframe, a main frame and asub-frame, with each of superframes containing 120 main frames, each ofmain frames containing 5 sub-frames, each of sub-frames containing 10words and each of words containing 30 bits and lasting 0.06 second, andamong the 5 sub-frames, sub-frame 1 is used to broadcast the presentsatellite's basic navigation information of the satellite navigationsystem and transmitted by 10 pages in a time division manner, sub-frame2 to sub-frame 4 are used to broadcast the integrity and differentialinformation of the satellite navigation system and transmittedrespectively by 6 pages in a time division manner, and sub-frame 5 isused to broadcast all the satellite almanacs, ionosphere information andtime synchronization information with other systems of the satellitenavigation system and transmitted by 120 pages in a time divisionmanner. After step S1202, the message broadcast method 120 for theenhanced parameter in the satellite navigation system is ended.

Optionally, although not shown in FIG. 12, the enhanced parametercomprises satellite clock difference correction parameters and partitioncomprehensive correction parameters, and the satellite clock differencecorrection parameters are inserted into a first group of predeterminedpositions in the reserved space of sub-frame 2 and sub-frame 3 andtransmitted by 6 pages in a time division manner, and the partitioncomprehensive correction parameters are inserted into a second group ofpredetermined positions in the reserved space of sub-frame 2 tosub-frame 4 and transmitted by the 12 pages in a time division manner.

Optionally, although not shown in FIG. 12, the enhanced parametercomprises partition comprehensive correction parameters, and thepartition comprehensive correction parameters comprise partitioncomprehensive corrections, area identifiers and satellite identifiers.Additionally, the area identifiers are used for, for each of areas inthe satellite navigation system, employing a 1-bit information bitrespectively to identify whether there is a partition comprehensivecorrection that needs to be broadcast, and the area identifiers areinserted into a third group of predetermined positions in the reservedspace of page 1 of sub-frame 2. Additionally, the satellite identifiersare used for, for each of satellites in the satellite navigation system,employing a 1-bit information bit respectively to identify whether thereis a partition comprehensive correction that needs to be broadcast, andthe satellite identifiers are inserted into a fourth group ofpredetermined positions in the reserved space of page 2 to page 4 ofsub-frame 2. Additionally, partition comprehensive corrections, whichcorrespond to different areas and different satellites respectively andneeds to be broadcast, are inserted into a fifth group of predeterminedpositions in the reserved space of page 1 to page 6 of sub-frame 3 andsub-frame 4 sequentially. Additionally, the broadcast period of thepartition comprehensive correction parameters is 30 seconds to 3minutes, preferably, it is 36 seconds. The embodiment of the presentinvention takes 36 seconds as an example, but is merely an example, nota limitation.

Optionally, although not shown in FIG. 12, a area index i and asatellite index j corresponding to each of the broadcast partitioncomprehensive corrections are respectively defined as follows: i=INT(n,x)+1; j=MOD(n, x). Wherein, n denotes the number of the broadcastpartition comprehensive correction, and x denotes the total number ofsatellites where there are partition comprehensive corrections thatneeds to be broadcast.

Optionally, although not shown in FIG. 12, the enhanced parametercomprises satellite clock difference correction parameters, and thesatellite clock difference correction parameters comprise satelliteidentifiers and satellite clock difference correction residues.Additionally, the satellite identifiers are used for, for each ofsatellites in the satellite navigation system, employing a 1-bitinformation bit respectively to identify whether there is a satelliteclock difference correction residue that needs to be broadcast, and thesatellite identifiers are inserted into a third group of predeterminedpositions in the reserved space of page 1 of sub-frame 2. Additionally,the satellite clock difference correction residues, which correspond todifferent satellites respectively and needs to be broadcast, areinserted into a sixth group of predetermined positions in the reservedspace of page 5 and page 6 of sub-frame 4 sequentially. Additionally,the broadcast period of the satellite clock difference correctionparameters is 18 seconds to 2 minutes, preferably 18 seconds. Theembodiment of the present invention takes the 18 seconds as an example,but is merely an example, not a limitation.

Optionally, although not shown in FIG. 12, a broadcast informationcategory identifier is inserted into a predetermined 1-bit informationbit in the reserved space of page 4 of sub-frame 2, and the satelliteclock difference correction residues are broadcast in the sixth group ofpredetermined positions when the broadcast information categoryidentifier is one of 1 and 0, and GPS satellite differential fast changeinformation is broadcast in the sixth group of predetermined positionswhen the broadcast information category identifier is the other of 1 and0.

Optionally, although not shown in FIG. 12, the enhanced parametercomprises GPS partition comprehensive correction parameters, and the GPSpartition comprehensive correction parameters comprise GPS partitioncomprehensive corrections, GPS area identifiers and GPS satelliteidentifiers. Additionally, the GPS area identifiers are used for, foreach of GPS areas, employing a 1-bit information bit respectively toidentify whether there is a GPS partition comprehensive correction thatneeds to be broadcast, and the GPS area identifiers are inserted into aseventh group of predetermined positions in the reserved space of page23 and page 83 of sub-frame 5. Additionally, the GPS satelliteidentifiers are used for, for each of GPS satellites, employing a 1-bitinformation bit respectively to identify whether there is a GPSpartition comprehensive correction that needs to be broadcast, and theGPS satellite identifiers are inserted into an eighth group ofpredetermined positions in the reserved space of page 23 and page 83 ofsub-frame 5. Additionally, the GPS partition comprehensive corrections,which correspond to different GPS areas and different GPS satellitesrespectively and needs to be broadcast, are inserted into a ninth groupof predetermined positions in the reserved space of page 23 to page 30and page 83 to page 90 of sub-frame 5 sequentially. Additionally, thebroadcast period of the GPS partition comprehensive correctionparameters is 30 seconds to 3 minutes and preferably 36 seconds. Theembodiment of the present invention takes 36 seconds as an example, butis merely an example, not a limitation.

Optionally, although not shown in FIG. 12, the enhanced parametercomprises satellite orbit correction parameters, and the satellite orbitcorrection parameters comprise satellite identifiers, satellitebroadcast ephemeris corrections and equivalent distance error statusidentifiers of satellite ephemeris corrections. Additionally, thesatellite identifiers are used for, for each of satellites in thesatellite navigation system, employing a 1-bit information bitrespectively to identify whether there are a satellite broadcastephemeris correction and an equivalent distance error status identifierof the satellite ephemeris correction that need to be broadcast, and thesatellite identifiers are inserted into a tenth group of predeterminedpositions in the reserved space of page 23 of sub-frame 5. Additionally,the satellite broadcast ephemeris corrections and the equivalentdistance error status identifiers of satellite ephemeris corrections,which correspond to different satellites respectively and need to bebroadcast, are inserted into a eleventh group of predetermined positionsin the reserved space of page 117 to page 120, page 31 and page 91 ofsub-frame 5. Additionally, the broadcast period of the satellite orbitcorrection parameters is 3-6 minutes and preferably 6 minutes. The 6minutes mentioned by the embodiment of the present invention is merelyan example, not a limitation.

Optionally, although not shown in FIG. 12, the byte size and thebroadcast frequency of the enhanced parameter are determined accordingto the quantization range and the quantization accuracy of the enhancedparameter respectively.

Optionally, although not shown in FIG. 12, the satellite navigationsystem is Beidou satellite navigation system.

The specific operation of various steps of the message broadcast method120 for the enhanced parameter in the satellite navigation system hasbeen described in detail in message broadcast apparatus 40 for theenhanced parameter in the satellite navigation system described withreference to FIGS. 1-11E, and will not be repeated here.

With the message broadcast method 120 for the enhanced parameter in thesatellite navigation system, by combining a frame and a data block in anavigation message structure, the satellite-and-earth-integratedflexible broadcast of the navigation message is realized, the basicnavigation information and the enhanced information can be uniformlybroadcast, the scalability of the navigation message is improved, theflexibility of message broadcasting is improved, the user's useperformance is improved, and the utilization of channel link resourcesis improved.

In the above, the message broadcast apparatus and method for theenhanced parameter in the satellite navigation system according toembodiments of the present invention is described with reference toFIGS. 4-12.

FIG. 13 is a block diagram of a receiver according to an embodiment ofthe present application. It should be noted that the receiver of theembodiment of the present invention includes but is not limited to aGNSS receiver, a handheld portable device, etc., and may be any moduleor apparatus with a function of navigation and positioning. Furthermore,the receiver of the embodiment of the present invention may be asingle-mode receiver or a multimode receiver.

Referring to FIG. 13, a receiver 1300 is divided into an antenna 1310, astorage apparatus 1320, a processing module 1330 and a user interactionmodule 1340 according to functions.

The receiver 1300 receives basic broadcast messages and correctionparameters broadcast by multiple satellites via the antenna 1310. Insome embodiments, the correction parameters include a partitioncomprehensive correction x₄, and in other embodiments, the correctionparameters include the partition comprehensive correction x₄ and furtherincludes at least one parameter of an orbit correction x₁, a clockdifference correction x₂ and an ionosphere correction x₃, wherein, theionosphere correction x₃ uses modules including, but not limited to, agrid ionosphere model, an 8-parameter model or a 14-parameter model, andpreferably uses the grid ionosphere model. The orbit correction is alsocalled the satellite orbit correction, and the clock differencecorrection is also called the satellite clock difference correction,which will no longer be described below.

The storage apparatus 1320 is coupled with the antenna 1310, and storesthe multiple basic broadcast messages and the above correctionparameters received and transmits them to the processing module 1330.

The processing module 1330 further processes the received multiple basicbroadcast messages and correction parameters to obtain a positioningposition of the receiver by operation, then the receiver transmits thedetermined positioning position to the user interaction module 1340 soas to indicate the obtained positioning result to the user.

Specifically, the positioning operation performed by the processingmodule is different according to the difference of correction parametersthat the receiver is able to receive and the difference of frequenciesreceived by the receiver, wherein, the partition comprehensivecorrection x₄ is used to comprehensively correct multiple errors, theorbit correction x₁ is used to correct the orbit error, the clockdifference correction x₂ is used to correct the clock difference error,and the ionosphere correction x₃ is used to correct the ionosphere delayerror, which will no longer be described below.

The procedure of the method for performing navigation and positioning ofa single-frequency, dual-frequency and tri-frequency receiver using apartition comprehensive correction or using the partition comprehensivecorrection in combination with other correction parameters will bedescribed by way of example with further reference to FIGS. 14-25 below.

First, refer to FIG. 14, which shows a flowchart of a navigation andpositioning method of a single-frequency receiver using correctionparameters including a partition comprehensive correction x₄, an orbitcorrection x₁, a clock difference correction x₂ and an ionospherecorrection x₃ according to an embodiment of the present application.

At step S1400, the processing module receives the basic broadcastmessages and the correction parameters including the orbit correctionx₁, the clock difference correction x₂, the ionosphere correction x₃ andthe partition comprehensive correction x₄ of N satellites, and theprocessing module obtains a single-frequency pseudorange observationequation P₁ and a carrier-phase observation equation L₁ for eachsatellite based on the broadcast ephemeris:

$\begin{matrix}{P_{1} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + I_{1} + T + ɛ_{P_{1}}}} & (1) \\{L_{1} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} - I_{1} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + ɛ_{L_{1}}}} & (2)\end{matrix}$

Wherein, P₁ and L₁ are pseudorange and carrier-phase observationfunctions respectively; ρ is a satellite-earth geometric distance (thecoordinate of the observation station); c is the speed of light, δt is aclock difference of the observation station, and δt^(s) is the satelliteclock difference calculated by the broadcast ephemeris; f₁ is a firstcarrier frequency; I₁ is an ionosphere delay at the first frequencycalculated using parameters of a broadcast ephemeris ionosphere model; Tis a troposphere delay correction; λ₁·N₁ is an unknown ambiguity; λ₁ isa carrier wavelength, W is a carrier-phase winding correction in unitsof weeks; ε_(P) ₁ , ε_(L) ₁ are observation noises of pseudorange andcarrier-phase respectively.

In addition, the definition and generation of the orbit correction x₁,the clock difference correction x₂, the ionosphere correction x₃ and thepartition comprehensive correction x₄ have been described in thespecification, and thus will no longer be described herein.

At step S1410, the established pseudorange observation equation andcarrier-phase observation equation are corrected by using all of theabove quadruple correction parameters x₁, x₂, x₃ and x₄, so that thecorrected pseudorange observation equation P₁(x) and carrier-phaseobservation equation L₁(x) may be obtained:

$\begin{matrix}{{P_{1}\left( {x_{1},x_{2},x_{3},x_{4}} \right)} = {\rho + {{\Delta\rho}\left( x_{1} \right)} + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} + {I_{1}\left( x_{3} \right)} + T + x_{4} + ɛ_{P_{1}}^{\prime}}} & (3) \\{{L_{1}\left( {x_{1},x_{2},x_{3},x_{4}} \right)} = {\rho + {{\Delta\rho}\left( x_{1} \right)} + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} - {I_{1}\left( x_{3} \right)} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + x_{4} + ɛ_{L_{1}}^{\prime}}} & (4)\end{matrix}$

In the above equation, Δρ(x₁) is the distance correction calculatedbased on the orbit correction x₁; x₂ is the clock difference correction;I₁(x₃) is the ionosphere delay at the first frequency calculated usingthe ionosphere correction x₃; ε_(L) ₁ ′ and ε_(P1)′ are theparameter-corrected observation noises after combing pseudorange andcarrier-phase, in which the partition comprehensive correction may useat least one or both of the GPS partition comprehensive correction andthe Beidou partition comprehensive correction.

At step S1420, by combining the above-described corrected pseudorangeobservation equation P₁(x) and carrier-phase observation equation L₁(x),that is, in equations (3) and (4), it can constitute a combination thateliminates the influence of the ionosphere, that is, an ionosphere-freecombined observation, as a first observation (the following equation(5)):

$\begin{matrix}{{{L_{1}\left( {x_{1},x_{2},x_{3},x_{4}} \right)} + {P_{1}\left( {x_{1},x_{2},x_{3},x_{4}} \right)}} = {\rho + {{\Delta\rho}\left( x_{1} \right)} + {{c \cdot \delta}\; t} - {c\left( {{\delta\; t^{s}} - x_{2}} \right)} + T + \frac{\lambda_{1} \cdot N_{1}}{2} + {\frac{c}{2f_{1}}W} + x_{4} + \frac{ɛ_{L_{1}}^{\prime} + ɛ_{P_{1}}^{\prime}}{2}}} & (5)\end{matrix}$

At step S1430, the corrected pseudorange observation equation P₁(x),that is, the above equation (3) is taken as a second observation.

At step S1440, by jointly solving the first observation and the secondobservation of each satellite of the N satellites, the operation resultof the user positioning is obtained. In order to solve all theparameters, the number N of satellites observed needs to be greater than4.

Specifically, the above equations (3) and (5) constitute observationequations for single-frequency navigation and positioning, and thecorresponding observation equations are:

$\begin{bmatrix}{\frac{{L_{1}\left( {x_{1},x_{2},x_{3},x_{4}} \right)} + {P_{1}\left( {x_{1},x_{2},x_{3},x_{4}} \right)}}{2} - \rho_{1} - D_{\frac{L_{1} + P_{1}}{2}}} \\{{P_{1}\left( {x_{1},x_{2},x_{3},x_{4}} \right)} - \rho_{1} - D_{P_{1}}} \\\vdots \\{\frac{{L_{n}\left( {x_{1},x_{2},x_{3},x_{4}} \right)} + {P_{n}\left( {x_{1},x_{2},x_{3},x_{4}} \right)}}{2} - \rho_{n} - D_{\frac{L_{n} + P_{n}}{2}}} \\{{P_{n}\left( {x_{1},x_{2},x_{3},x_{4}} \right)} - \rho_{n} - D_{P_{n}}}\end{bmatrix} = {\quad{{{\left\lbrack \begin{matrix}\frac{X_{0} - X^{1}}{\rho} & \frac{Y_{0} - Y^{1}}{\rho} & \frac{Z_{0} - Z^{1}}{\rho} & 1 & M_{wet}^{1} & 0 & {\dddot{}} & 0 \\\frac{X_{0} - X^{1}}{\rho} & \frac{Y_{0} - Y^{1}}{\rho} & \frac{Z_{0} - Z^{1}}{\rho} & 1 & M_{wet}^{1} & 1 & {\dddot{}} & 0 \\\; & \; & \vdots & \; & \; & \; & \; & \; \\\frac{X_{0} - X^{n}}{\rho} & \frac{Y_{0} - Y^{n}}{\rho} & \frac{Z_{0} - Z^{n}}{\rho} & 1 & M_{wet}^{n} & 0 & {\dddot{}} & 0 \\\frac{X_{0} - X^{n}}{\rho} & \frac{Y_{0} - Y^{n}}{\rho} & \frac{Z_{0} - Z^{n}}{\rho} & 1 & M_{wet}^{n} & 0 & {\dddot{}} & 1\end{matrix} \right\rbrack\left\lbrack \begin{matrix}{dX} \\{dY} \\{dZ} \\{{c \cdot \delta}\; t} \\{dZTD}_{w} \\B_{1} \\\vdots \\B_{n}\end{matrix} \right\rbrack}\mspace{79mu}{wherein}\mspace{76mu} D_{\frac{L + P}{2}}} = {{{{\Delta\rho}\left( x_{1} \right)} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} + T + {\frac{c}{2f_{1}}W} + {x_{4}\mspace{76mu} D_{P}}} = {{{\Delta\rho}\left( x_{1} \right)} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} + {I_{1}\left( x_{3} \right)} + T + x_{4}}}}}$

In the equation, [X₀, Y₀, Z₀] is the approximate coordinate of theobservation station; [X¹, Y¹, Z¹ ⋅ ⋅ ⋅ X^(n), Y^(n), Z^(n)] is thecoordinate of a satellite; [dX, dY, dZ] is the coordinate correctionparameters of the observation station; M_(wet) is the troposphere wetdelay mapping function; dZTD_(W) is the troposphere wet zenith delaycorrection parameters; w is the carrier-phase winding correction; B isthe carrier-phase ambiguity parameter in units of distance. According tothe above observation equation, those skilled in the art can solve thefinal operation result of the user positioning.

In addition, because the accuracies of different observation equationsare not uniform, it is necessary to perform weight determination on theobservation equations (that is, configure the corresponding weightingratios for the observations) and establish a stochastic model thereof.The observation equation noise is mainly composed of the errors ofrespective models:σ²=σ_(eph) ²+σ_(clk) ²+σ_(ion) ²+σ_(trop) ²+σ_(mp) ²+σ_(noise) ²

In the above equation, σ is the observation equation noise, and σ_(eph),σ_(clk), σ_(ion), σ_(trop), σ_(mp), σ_(noise) indicate the satelliteorbit accuracy, the satellite clock difference accuracy, the ionospheremodel accuracy, the troposphere model accuracy, the multipath modelaccuracy, and the observation noise accuracy respectively. Further, inorder to simplify the models, the above observation equation can bedivided into components (σ_(eph),σ_(clk)) that are independent of theelevation angle, and other parts are classified as components related tothe elevation angle (σ²(ele)), as follows:σ²=σ_(eph) ²+σ_(clk) ²+σ²(ele)

In the above equation, the weight of σ⁻²(ele) is generally determinedaccording to the elevation angle:

$\quad\left\{ \begin{matrix}{{{\sigma({ele})} = \sigma_{0}},{{ele} > {30{^\circ}}}} \\{{{\sigma({ele})} = \frac{\sigma_{0}}{2{\sin({ele})}}},{{ele} \leq {30{^\circ}}}}\end{matrix} \right.$

Therefore, the stochastic model is as follows:

$Q = {R^{- 1} = \begin{bmatrix}\frac{1}{\sigma_{1}^{2}} & \; & \; \\\; & \ddots & \; \\\; & \; & \frac{1}{\sigma_{n}^{2}}\end{bmatrix}}$

In the above equation, Q is the weight matrix of the observation, R isthe covariance matrix of the observation. Through the solution of theabove-mentioned weight matrix of the observation, the empirical value ofthe weighting ratio of the observation can be obtained as: the amplituderange of the weighting ratio is from 1:0.01 to 1:0.05, and the optimalweighting ratio is preferably 1:0.05.

Next, a navigation and positioning method of a dual-frequency receiverusing correction parameters including a partition comprehensivecorrection x₄, an orbit correction x₁, a clock difference correction x₂and an ionosphere correction x₃ according to an embodiment of thepresent application is described with reference to FIG. 15.

At step S1500, since it is a dual-frequency receiver, the processingmodule here, in addition to receiving parameters and establishing thepseudo-range observation equation P₁ (i.e., equation (1)) and thecarrier-phase observation equation L₁ (i.e., equation (2)) of the firstfrequency f₁ as described above with reference to FIG. 14:

$\begin{matrix}{P_{1} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + I_{1} + T + ɛ_{P_{1}}}} & (1) \\{L_{1} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} - I_{1} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + ɛ_{L_{1}}}} & (2)\end{matrix}$further introduces a pseudo-range observation P₂ (that is, equation (6))and a carrier-phase observation L₂ (that is, equation (7)) of a secondfrequency f₂ other than the first frequency f₁:

$\begin{matrix}{P_{2} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + I_{2} + T + ɛ_{P_{2}}}} & (6) \\{L_{2} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} - I_{2} + T + {\lambda_{2} \cdot N_{2}} + {\frac{c}{f_{2}}W} + ɛ_{L_{2}}}} & (7)\end{matrix}$

The meanings of the variables in the above equations (6) and (7) are thesame as those in the equations (1) and (2), except that here it is thesecond frequency f₂ which is different from the first frequency f₁.

At step S1510, the established pseudorange observation equations(equation (1) and equation (6)) and carrier-phase observation equations(equations (2) and (7)) are corrected by using the correction parameters(the correction parameters include the partition comprehensivecorrection x₄, the orbit correction x₁, the clock difference correctionx₂ and the ionosphere correction x₃), so that the corrected pseudorangeobservation equation P₁(x) (i.e., equation (3)) and carrier-phaseobservation equation L₁(x) (i.e., equation (4)) of the first frequencyand the corrected pseudorange observation equation P₂(x) (i.e., equation(8)) and carrier-phase observation equation L₂(x) (i.e., equation (9))of the second frequency may be obtained:

$\begin{matrix}{{P_{1}\left( {x_{1},x_{2},x_{3},x_{4}} \right)} = {\rho + {{\Delta\rho}\left( x_{1} \right)} + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} + {I_{1}\left( x_{3} \right)} + T + x_{4} + ɛ_{P_{1}}^{\prime}}} & (3) \\{{L_{1}\left( {x_{1},x_{2},x_{3},x_{4}} \right)} = {\rho + {{\Delta\rho}\left( x_{1} \right)} + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} - {I_{1}\left( x_{3} \right)} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + x_{4} + ɛ_{L_{1}}^{\prime}}} & (4) \\{{P_{2}\left( {x_{1},x_{2},x_{3},x_{4}} \right)} = {\rho + {{\Delta\rho}\left( x_{1} \right)} + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} + {I_{2}\left( x_{3} \right)} + T + x_{4} + ɛ_{P_{2}}^{\prime}}} & (8) \\{{L_{2}\left( {x_{1},x_{2},x_{3},x_{4}} \right)} = {\rho + {{\Delta\rho}\left( x_{1} \right)} + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} - {I_{2}\left( x_{3} \right)} + T + {\lambda_{2} \cdot N_{2}} + {\frac{c}{f_{2}}W} + x_{4} + ɛ_{L_{2}}^{\prime}}} & (9)\end{matrix}$

The meanings of the variables in the above equations (8) and (9) are thesame as those in the equations (3) and (4).

At step S1520, the carrier-phase observation equation L₁(x) and thecarrier-phase observation equation L₂(x) of the above equations (4) and(9) are combined to construct a carrier-phase ionosphere-freecombination, that is, a first observation:

$\begin{matrix}{L_{IF} = \frac{{f_{1}^{2}{L_{1}\left( {x_{1},x_{2},x_{3},x_{4}} \right)}} - {f_{2}^{2}{L_{2}\left( {x_{1},x_{2},x_{3},x_{4}} \right)}}}{f_{1}^{2} - f_{2}^{2}}} & (10)\end{matrix}$

At step S1530, the pseudorange observation equation P₁(x) and thepseudorange observation equation P₂(x) of the above equations (3) and(8) are combined to construct a pseudorange ionosphere-free combination,that is, a second observation:

$\begin{matrix}{P_{IF} = \frac{{f_{1}^{2}{P_{1}\left( {x_{1},x_{2},x_{3},x_{4}} \right)}} - {f_{2}^{2}{P_{2}\left( {x_{1},x_{2},x_{3},x_{4}} \right)}}}{f_{1}^{2} - f_{2}^{2}}} & (11)\end{matrix}$

At step S1540, the first observation and the second observation of eachof the N satellites are jointly solved by a solution procedure similarto the above, to obtain the operation result of the user positioning,where N is greater than 4. It should be noted that, in the procedure ofjoint solution, the weighting ratios of the observations are configuredby the above weight determination formula similar to that in step S1440,so that it can be obtained that the range of the weighting ratio is from1:0.01 to 1:0.05, with the optimal weighting ratio being preferred as1:0.01.

On the other hand, in the use procedure of the user, in order tosimplify the processing procedure of the receiver, it is also possibleto receive and use only a part of the quadruple correction parameters tocorrect the operation result. In other words, the receiver can receiveor use only the partition comprehensive correction x₄ and anycombination of the triple correction parameters, the orbit correctionx₁, the clock difference correction x₂ and the ionosphere correction x₃,to correct the positioning operation. In the following, the descriptionwill be made through an example in which the processing module receivesor uses only the triple correction parameters, the partitioncomprehensive correction x₄, the clock difference correction x₂ and theionosphere correction x₃. However, it should also be noted that, as willbe understood by those skilled in the art, the scheme of the presentapplication is not limited to the following embodiment, but may beapplied to the technical schemes using the partition comprehensivecorrection x₄ and one or any two of the other three correctionparameters.

FIG. 16 shows a flowchart of a navigation and positioning method of asingle-frequency receiver using correction parameters including apartition comprehensive correction x₄, a clock difference correction x₂and an ionosphere correction x₃ according to an embodiment of thepresent application.

Referring to FIG. 16, at step S1600, the processing module receivesbasic broadcast messages, partition comprehensive corrections x₄ and atleast one of orbit corrections x₁, clock difference corrections x₂ andionosphere corrections x₃ of N satellites. For example, in thisembodiment, the correction parameters received or used include thepartition comprehensive corrections x₄, the clock difference correctionsx₂ and the ionosphere corrections x₃.

Based on the broadcast ephemeris, the single-frequency pseudorangeobservation equation P₁ and carrier-phase observation equation L₁ ofeach satellite can be, like the above, written as:

$\begin{matrix}{P_{1} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + I_{1} + T + ɛ_{P_{1}}}} & (1) \\{L_{1} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} - I_{1} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + ɛ_{L_{1}}}} & (2)\end{matrix}$

The definition of the parameters is as described above, and thus will nolonger be described.

At step S1610, the established pseudorange observation equation(equation (1)) and carrier-phase observation equation (equation (2)) arecorrected by using correction parameters, with the correction parametersincluding the partition comprehensive correction x₄, the clock errorcorrection x₂ and the ionosphere correction x₃. In this way, thepseudorange observation equation P₁(x) (equation (13)) and thecarrier-phase observation equation L₁(x) (equation (12)) corrected bythe correction parameters can be obtained:

$\begin{matrix}{{L_{1}\left( {x_{2},x_{3},x_{4}} \right)} = {\rho + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} - {I_{1}\left( x_{3} \right)} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + x_{4} + ɛ_{L_{1}}^{\prime}}} & (12)\end{matrix}\begin{matrix}{\;{{P_{1}\left( {x_{2},x_{3},x_{4}} \right)} = {\rho + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} + {I_{1}\left( x_{3} \right)} + T + x_{4} + ɛ_{P_{1}}^{\prime}}}} & (13)\end{matrix}$

The definition of the parameters is as described above, and thus will nolonger be described. The partition comprehensive correction may use atleast one or both of the GPS partition comprehensive correction and theBeidou partition comprehensive correction. Here, the Beidou partitioncomprehensive correction is taken as an example.

At step S1620, by combining the above pseudorange observation equationP₁(x) (equation (13)) and carrier-phase observation equation L₁(x)(equation (12)) corrected, i.e., in equations (12), (13), it canconstitute a combination that eliminates the influence of theionosphere, that is, anionosphere-free combined observation, as a firstobservation (the following equation (14)):

$\begin{matrix}{\frac{{L_{1}\left( {x_{2},x_{3},x_{4}} \right)} + {P_{1}\left( {x_{2},x_{3},x_{4}} \right)}}{2} = {\rho + {{c \cdot \delta}\; t} - {c\left( {{\delta\; t^{s}} - x_{2}} \right)} + T + \frac{\lambda_{1} \cdot N_{1}}{2} + {\frac{c}{2f_{1}}W} + x_{4} + \frac{ɛ_{L_{1}}^{\prime} + ɛ_{P_{1}}^{\prime}}{2}}} & (14)\end{matrix}$

At step S1630, the corrected pseudorange observation equation P₁(x),that is, the above equation (13), is taken as a second observation.

At step S1640, the first observation (equation (14)) and the secondobservation (equation (13)) of each of the N satellites are jointlysolved to obtain the operation result of the user positioning, where Nis greater than 4. It should be noted that, in the procedure of thejoint solution, the weighting ratios of the observations are configuredby the above weight determination formula similar to that in step S1440,so that it can be obtained that the weighting ratio of experience hereis optimally preferred as 1:0.05 and that the amplitude range of theweighting ratio is from 1:0.01 to 1:0.05.

FIG. 17 shows a flowchart of a navigation and positioning method of adual-frequency receiver using correction parameters including apartition comprehensive correction x₄, a clock difference correction x₂and an ionosphere correction x₃ according to another embodiment of thepresent application.

At step S1700, since it is a dual-frequency receiver, the processingmodule here, in addition to receiving parameters and establishing thepseudo-range observation equation P₁ (i.e., equation (1)) and thecarrier-phase observation equation L₁ (i.e., equation (2)) of the firstfrequency f₁ as described above with reference to FIG. 14:

$\begin{matrix}{P_{1} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + I_{1} + T + ɛ_{P_{1}}}} & (1) \\{L_{1} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} - I_{1} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + ɛ_{L_{1}}}} & (2)\end{matrix}$further introduces a pseudo-range observation P₂ (i.e., equation (15))and a carrier-phase observation L₂ (i.e., equation (16)) of a secondfrequency f₂ other than the first frequency f₁:

$\begin{matrix}{P_{2} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + I_{2} + T + ɛ_{P_{2}}}} & (15) \\{L_{2} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} - I_{2} + T + {\lambda_{2} \cdot N_{2}} + {\frac{c}{f_{1}}W} + ɛ_{L_{2}}}} & (16)\end{matrix}$

The definition of the parameters is as described above, and thus will nolonger be described.

The meanings of the variables in the above equations (15) and (16) arethe same as those in the equations (1) and (2), only except that thesecond frequency f₂ is different from the first frequency f₁.

At step S1710, the established pseudorange observation equations(equation (1) and equation (15)) and carrier-phase observation equations(equation (2) and equation (16)) are corrected by using the correctionparameters (including the partition comprehensive correction x₄, theclock difference correction x₂ and the ionosphere correction x₃), sothat the corrected pseudorange observation equation P₁(x) (equation(17)) and carrier-phase observation equation L₁(x) (equation (18)) ofthe first frequency f₁ and the corrected pseudorange observationequation P₂(x) (equation (19)) and carrier-phase observation equationL₂(x) (equation (20)) of the second frequency f₂ may be obtained:

$\begin{matrix}{{P_{1}\left( {x_{2},x_{3},x_{4}} \right)} = {\rho + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} + {I_{1}\left( x_{3} \right)} + T + x_{4} + ɛ_{P_{1}}^{\prime}}} & (17) \\{{L_{1}\left( {x_{2},x_{3},x_{4}} \right)} = {\rho + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} - {I_{1}\left( x_{3} \right)} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + x_{4} + ɛ_{L_{1}}^{\prime}}} & (18) \\{\mspace{79mu}{{P_{2}\left( {x_{2},x_{3},x_{4}} \right)} = {\rho + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} + {I_{2}\left( x_{3} \right)} + T + ɛ_{P_{2}}^{\prime}}}} & (19) \\{{L_{2}\left( {x_{2},x_{3},x_{4}} \right)} = {\rho + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} - {I_{2}\left( x_{3} \right)} + T + {\lambda_{2} \cdot N_{2}} + {\frac{c}{f_{2}}W} + ɛ_{L_{2}}^{\prime}}} & (20)\end{matrix}$

The meanings of the variables in the above equations (19) and (20) arethe same as those in the equations (17) and (18).

At step S1720, the carrier-phase observation equation L₁(x) and thecarrier-phase observation equation L₂(x) of the above equations (18) and(20) are combined to construct a carrier-phase ionosphere-freecombination, that is, a first observation:

$\begin{matrix}{L_{IF} = \frac{{f_{1}^{2}{L_{1}\left( {x_{2},x_{3},x_{4}} \right)}} - {f_{2}^{2}{L_{2}\left( {x_{2},x_{3},x_{4}} \right)}}}{f_{1}^{2} - f_{2}^{2}}} & (21)\end{matrix}$

At step S1730, the pseudorange observation equation P₁(x) and thepseudorange observation equation P₂(x) of the above equations (17) and(19) are combined to construct a pseudorange ionosphere-freecombination, that is, a second observation:

$\begin{matrix}{P_{IF} = \frac{{f_{1}^{2}{P_{1}\left( {x_{2},x_{3},x_{4}} \right)}} - {f_{2}^{2}{P_{2}\left( {x_{2},x_{3},x_{4}} \right)}}}{f_{1}^{2} - f_{2}^{2}}} & (22)\end{matrix}$

At step S1740, the first observation (equation (21)) and the secondobservation (equation (22)) of each of the N satellites are jointlysolved to obtain the operation result of the user positioning, where Nis greater than 4. It should be noted that, in the procedure of jointsolution, the weighting ratios of the observations are configured by theabove weight determination formula similar to that in step S1440, sothat it can be obtained that the weighting ratio is optimally preferredas 1:0.01 and that the amplitude range of the weighting ratio is from1:0.01 to 1:0.05.

With the above description, those skilled in the art have alreadyunderstood the principles and operation modes of the single-frequencyand dual-frequency receivers implemented according to the embodiments ofthe present invention. It can be understood that the operation principleof the tri-frequency receiver implemented according to an embodiment ofthe present invention is also similar to the content described above. Inthe following, various implementations of a tri-frequency receiver andits navigation and positioning method according to embodiments of thepresent application will be explained by way of example with referenceto FIGS. 18-21, with the description of the principle same with those ofthe single-frequency and dual-frequency receiver sections being omittedto avoid unnecessary confusion.

Firstly, referring to FIG. 18, which shows a flowchart of a navigationand positioning method of a tri-frequency receiver using correctionparameters including a partition comprehensive correction x₄, an orbitcorrection x₁, a clock difference correction x₂ and an ionospherecorrection x₃ according to an embodiment of the present application. Inone implementation, the processing module of the tri-frequency receivercan make a choice for the received observation data of three differentfrequencies.

For example, at step S1800, the processing module here receives theobservation parameters corresponding to three frequencies f₁, f₂, f₃respectively, and the processing module can select any two frequenciesthereof (for example, the processing module can select frequencies f₁and f₂, or select frequencies f₁ and f₃, or select frequencies f₂ andf₃) and establish pseudorange observation equations and carrier-phaseobservation equations for the selected two frequencies.

For example, assuming that the frequencies selected by the processingmodule are f₁ and f₂, a pseudorange observation equation P₁ and acarrier-phase observation equation L₁ corresponding to the firstfrequency f₁ and a pseudo observation equation P₂ and a carrier-phaseobservation equation L₂ corresponding to the second frequency f₂ arerespectively established for the two frequencies:

$\begin{matrix}{L_{1} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} - I_{1} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + ɛ_{L_{1}}}} & (1) \\{L_{1} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} - I_{1} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + ɛ_{L_{1}}}} & (2) \\{P_{2} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + I_{2} + T + ɛ_{P_{2}}}} & (6) \\{L_{2} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} - I_{2} + T + {\lambda_{2} \cdot N_{2}} + {\frac{c}{f_{2}}W} + ɛ_{L_{2}}}} & (7)\end{matrix}$

Here, the above observation equations are the same as the equations atstep S1500, and the meanings of their variables are also the same, andtherefore will no longer be described here.

At step S1810, the established pseudorange observation equations(equation (1) and equation (6)) and carrier-phase observation equations(equations (2) and (7)) are corrected by using the correction parameters(the correction parameters include the partition comprehensivecorrection x₄, the orbit correction x₁, the clock difference correctionx₂ and the ionosphere correction x₃), so that the pseudorangeobservation equation P₁(x) (i.e., equation (3)) and carrier-phaseobservation equation L₁(x) (i.e., equation (4)) of the first frequencycorrected by the correction parameters and the corrected pseudorangeobservation equation P₂(x) (i.e., equation (8)) and carrier-phaseobservation equation L₂(x) (i.e., equation (9)) of the second frequencymay be obtained. The observation equations corrected by the correctionparameters are the same as the equations (3), (4), (8) and (9) at stepS1510, and therefore will no longer be described here.

At step S1820, similar to step S1520, the carrier-phase observationequation L₁(x) and the carrier-phase observation equation L₂(x) of theequations (4) and (9) are combined to construct a carrier-phaseionosphere-free combination, that is, a first observation:

$\begin{matrix}{L_{IF} = \frac{{f_{1}^{2}{L_{1}\left( {x_{1},x_{2},x_{3},x_{4}} \right)}} - {f_{2}^{2}{L_{2}\left( {x_{1},x_{2},x_{3},x_{4}} \right)}}}{f_{1}^{2} - f_{2}^{2}}} & (10)\end{matrix}$

At step S1830, similar to S1530, the pseudorange observation equationP₁(x) and the pseudorange observation equation P₂(x) of the equations(3) and (8) are combined to construct a pseudorange ionosphere-freecombination, that is, a second observation:

$\begin{matrix}{P_{IF} = \frac{{f_{1}^{2}{P_{1}\left( {x_{1},x_{2},x_{3},x_{4}} \right)}} - {f_{2}^{2}{P_{2}\left( {x_{1},x_{2},x_{3},x_{4}} \right)}}}{f_{1}^{2} - f_{2}^{2}}} & (11)\end{matrix}$

At step S1840, the first observation and the second observation of eachof the N satellites are jointly solved by a solution procedure similarto the above, to obtain the operation result of the user positioning,where N is greater than 4. It should be noted that, in the procedure ofjoint solution, the weighting ratios of the observations are configuredby the above weight determination formula similar to that in step S1440,so that it can be obtained that the range of the weighting ratio is from1:0.01 to 1:0.05, with the optimal weighting ratio being preferred as1:0.01.

Similarly, in the use procedure of the user, the correction parametersused may further include at least one of the orbit correction x₁, theclock difference correction x₂ and the ionosphere correction x₃ on thebasis of including the partition comprehensive correction x₄. Forexample, refer to FIG. 19, which shows a flowchart of a navigation andpositioning method of a tri-frequency receiver using correctionparameters including a partition comprehensive correction x₄, a clockdifference correction x₂ and an ionosphere correction x₃ according toanother embodiment of the present application.

At step S1900, the processing module here receives the observationparameters corresponding to three frequencies f₁, f₂, f₃ respectively,and the processing module can select any two frequencies thereof (forexample, the processing module can select frequencies f₁ and f₂, orselect frequencies f₁ and f₃, or select frequencies f₂ and f₃) andestablish pseudorange observation equations and carrier-phaseobservation equations for the selected two frequencies.

For example, assuming that the frequencies selected by the processingmodule are f₁ and f₂, a pseudorange observation equation P₁ and acarrier-phase observation equation L₁ corresponding to the firstfrequency f₁ and a pseudo observation equation P₂ and a carrier-phaseobservation equation L₂ corresponding to the second frequency f₂ arerespectively established for the two frequencies:

$\begin{matrix}{P_{1} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + I_{1} + T + ɛ_{P_{1}}}} & (1) \\{L_{1} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} - I_{1} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + ɛ_{L_{1}}}} & (2) \\{P_{2} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + I_{2} + T + ɛ_{P_{2}}}} & (15) \\{L_{2} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} - I_{2} + T + {\lambda_{2} \cdot N_{2}} + {\frac{c}{f_{2}}W} + ɛ_{L_{2}}}} & (16)\end{matrix}$

The definition of the parameters is as described above, and thus will nolonger be described.

At step S1910, the established pseudorange observation equations andcarrier-phase observation equations are corrected by using thecorrection parameters (the correction parameters include the partitioncomprehensive correction x₄, the clock difference correction x₂ and theionosphere correction x₃), so that the corrected pseudorange observationequation P₁(x) (equation (17)) and carrier-phase observation equationL₁(x) (equation (18)) of the first frequency f₁ and the correctedpseudorange observation equation P₂(x) (equation (19)) and carrier-phaseobservation equation L₂(x) (equation (20)) of the second frequency f₂may be obtained:

$\begin{matrix}{{P_{1}\left( {x_{2},x_{3},x_{4}} \right)} = {\rho + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} + {I_{1}\left( x_{3} \right)} + T + x_{4} + ɛ_{P_{1}}^{\prime}}} & (17) \\{{L_{1}\left( {x_{2},x_{3},x_{4}} \right)} = {\rho + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} - {I_{1}\left( x_{3} \right)} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + x_{4} + ɛ_{L_{1}}^{\prime}}} & (18) \\{{P_{2}\left( {x_{2},x_{3},x_{4}} \right)} = {\rho + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} + {I_{2}\left( x_{3} \right)} + T + x_{4} + ɛ_{P_{2}}^{\prime}}} & (19) \\{{L_{2}\left( {x_{2},x_{3},x_{4}} \right)} = {\rho + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} - {I_{2}\left( x_{3} \right)} + T + {\lambda_{2} \cdot N_{2}} + {\frac{c}{f_{2}}W} + x_{4} + ɛ_{L_{2}}^{\prime}}} & (20)\end{matrix}$

The meanings of the variables in the above equations (19) and (20) arethe same as those in the equations (17) and (18).

At step S1920, the carrier-phase observation equation L₁(x) and thecarrier-phase observation equation L₂(x) of the above equations (18) and(20) are combined to construct a carrier-phase ionosphere-freecombination, that is, a first observation:

$\begin{matrix}{L_{IF} = \frac{{f_{1}^{2}{L_{1}\left( {x_{2},x_{3},x_{4}} \right)}} - {f_{2}^{2}{L_{2}\left( {x_{2},x_{3},x_{4}} \right)}}}{f_{1}^{2} - f_{2}^{2}}} & (21)\end{matrix}$

At step S1930, the pseudorange observation equation P₁(x) and thepseudorange observation equation P₂(x) of the above equations (17) and(19) are combined to construct a pseudorange ionosphere-freecombination, that is, a second observation:

$\begin{matrix}{P_{IF} = \frac{{f_{1}^{2}{P_{1}\left( {x_{2},x_{3},x_{4}} \right)}} - {f_{2}^{2}{P_{2}\left( {x_{2},x_{3},x_{4}} \right)}}}{f_{1}^{2} - f_{2}^{2}}} & (22)\end{matrix}$

At step S1940, the first observation (equation (21)) and the secondobservation (equation (22)) of each of the N satellites are jointlysolved to obtain the operation result of the user positioning, where Nis greater than 4. Similarly, it should be noted that, in the procedureof joint solution, the weighting ratios of the observations areconfigured by the above weight determination formula similar to that instep S1440, so that it can be obtained that the weighting ratio isoptimally preferred as 1:0.01 and that the amplitude range of theweighting ratio is from 1:0.01 to 1:0.05.

In addition, the navigation and positioning method using tri-frequencyis not limited to the above implementation of selecting two frequenciesthereof; instead, a method of simultaneously using three frequencies toperform navigation and positioning operation can be realized. Forexample, FIGS. 20-21 show flowcharts of navigation and positioningmethods for another tri-frequency receiver using correction parametersaccording to embodiments of the present application.

Refer to FIG. 20, which shows a flowchart of a navigation andpositioning method of a tri-frequency receiver using correctionparameters including a partition comprehensive correction x₄, an orbitcorrection x₁, a clock difference correction x₂ and an ionospherecorrection x₃ according to an embodiment of the present application.

At step S2000, since it is a tri-frequency receiver, the processingmodule here receives observation parameters corresponding to threefrequencies f₁, f₂, f₃ respectively, and the processing modulerespectively establishes three pseudorange observations P₁ (equation(1)), P₂ (equation (15)), P₃ (equation (23)) and three carrier-phaseobservations L₁ (equation (2)), L₂ (equation (16)), L₃ (equation (24))corresponding to f₁, f₂ and f₃:

$\begin{matrix}{P_{1} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + I_{1} + T + ɛ_{P_{1}}}} & (1) \\{L_{1} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} - I_{1} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + ɛ_{L_{1}}}} & (2) \\{P_{2} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + I_{2} + T + ɛ_{P_{2}}}} & (15) \\{L_{2} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} - I_{2} + T + {\lambda_{2} \cdot N_{2}} + {\frac{c}{f_{2}}W} + ɛ_{L_{2}}}} & (16) \\{P_{3} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + I_{3} + T + ɛ_{P_{3}}}} & (23) \\{L_{3} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} - I_{3} + T + {\lambda_{3} \cdot N_{3}} + {\frac{c}{f_{3}}W} + ɛ_{L_{3}}}} & (24)\end{matrix}$

The definition of the parameters is as described above, and thus will nolonger be described.

At step S2010, the established three groups of pseudorange observationequations (equation (1), equation (15) and equation (23)) andcarrier-phase observation equations (equation (2), equation (6) andequation (24)) are corrected by using the correction parameters (thecorrection parameters include the partition comprehensive correction x₄,the orbit correction x₁, the clock difference correction x₂ and theionosphere correction x₃), so that the corrected pseudorange observationequation P₁(x) (equation (3)) and carrier-phase observation equationL₁(x) (equation (4)) of the first frequency f₁, the correctedpseudorange observation equation P₂(x) (equation (8)) and carrier-phaseobservation equation L₂(x) (equation (9)) of the second frequency f₂,and the corrected pseudorange observation equation P₃(x) (equation (25))and carrier-phase observation equation L₃(x) (equation (26)) of thesecond frequency f₃ may be obtained:

$\begin{matrix}{{P_{1}\left( {x_{1},x_{2},x_{3},x_{4}} \right)} = {\rho + {{\Delta\rho}\left( x_{1} \right)} + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} + {I_{1}\left( x_{3} \right)} + T + x_{4} + ɛ_{P_{1}}^{\prime}}} & (3) \\{{L_{1}\left( {x_{1},x_{2},x_{3},x_{4}} \right)} = {\rho + {{\Delta\rho}\left( x_{1} \right)} + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} - {I_{1}\left( x_{3} \right)} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + x_{4} + ɛ_{L_{1}}^{\prime}}} & (4) \\{{P_{2}\left( {x_{1},x_{2},x_{3},x_{4}} \right)} = {\rho + {{\Delta\rho}\left( x_{1} \right)} + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} + {I_{2}\left( x_{3} \right)} + T + x_{4} + ɛ_{P_{2}}^{\prime}}} & (8) \\{{L_{2}\left( {x_{1},x_{2},x_{3},x_{4}} \right)} = {\rho + {{\Delta\rho}\left( x_{1} \right)} + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} - {I_{2}\left( x_{3} \right)} + T + {\lambda_{2} \cdot N_{2}} + {\frac{c}{f_{2}}W} + x_{4} + ɛ_{L_{2}}^{\prime}}} & (9) \\{{P_{3}\left( {x_{1},x_{2},x_{3},x_{4}} \right)} = {\rho + {{\Delta\rho}\left( x_{1} \right)} + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} + {I_{3}\left( x_{3} \right)} + T + x_{4} + ɛ_{P_{3}}^{\prime}}} & (25) \\{{L_{3}\left( {x_{1},x_{2},x_{3},x_{4}} \right)} = {\rho + {{\Delta\rho}\left( x_{1} \right)} + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} - {I_{3}\left( x_{3} \right)} + T + {\lambda_{3} \cdot N_{3}} + {\frac{c}{f_{3}}W} + x_{4} + ɛ_{L_{3}}^{\prime}}} & (26)\end{matrix}$

At step S2020, the above carrier-phase observation equationsL₁(x₁−x₄)−L₃(x₁−x₄) corrected by the correction parameters are combinedto construct a carrier-phase ionosphere-free combination, that is, afirst observation (equation (29)):(αL ₁(x ₁ ,x ₂ ,x ₃ ,x ₄)+βL ₂(x ₁ ,x ₂ ,x ₃ ,x ₄)+γL ₃(x ₁ ,x ₂ ,x ₃ ,x₄))/F(α,β,γ)  (29)

α,β, γ are the corresponding coefficients of three frequencyobservations respectively, F(α,β, γ) are the combination ofcoefficients, the selection of α,β, γ and F(α,β, γ) are applicable to acombination commonly used by a tri-frequency receiver currently, and theionosphere is eliminated by the above combination.

At step S2030, the above pseudorange observation equationsP₁(x₁−x₄)−P₃(x₁−x₄) corrected by the correction parameters are combinedto construct a pseudorange ionosphere-free combination, that is, asecond observation (equation (30)):(αP ₁(x ₁ ,x ₂ ,x ₃ ,x ₄)+βP ₂(x ₁ ,x ₂ ,x ₃ ,x ₄)+γP ₃(x ₁ ,x ₂ ,x ₃ ,x₄))/F(α,β,γ)  (30)

α,β, γ are the corresponding coefficients of three frequencyobservations respectively, F(α,β, γ) are the combination ofcoefficients, the selection of α,β, γ and F(α,β, γ) are applicable to acombination commonly used by a tri-frequency receiver currently, and theionosphere is eliminated by the above combination.

At step S2040, the first observation and the second observation of eachof the N satellites are jointly solved by a solution procedure similarto the above, to obtain the operation result of the user positioning,where N is greater than 4. It should be noted that, in the procedure ofjoint solution, the weighting ratios of the observations are configuredby the above weight determination formula similar to that in step S1440,so that it can be obtained that the range of the weighting ratio is from1:0.01 to 1:0.05, with the optimal weighting ratio being preferred as1:0.01.

In addition, in the use procedure of the user, in order to simplify theprocessing procedure of the receiver, it is also possible to receive anduse only a part of the quadruple correction parameters to correct theoperation result. For example, refer to FIG. 21, which shows a flowchartof a navigation and positioning method of a tri-frequency receiver usingcorrection parameters including a partition comprehensive correction x₄,a clock difference correction x₂ and an ionosphere correction x₃according to an embodiment of the present application.

At step S2100, since it is a tri-frequency receiver, the processingmodule here receives observation parameters corresponding to threefrequencies f₁, f₂, f₃ respectively, and the processing modulerespectively establishes three pseudorange observations P₁ (equation(1)), P₂ (equation (15)), P₃ (equation (23)) and three carrier-phaseobservations L₁ (equation (2)), L₂ (equation (16)), L₃ (equation (24))corresponding to f₁, f₂ and f₃:

$\begin{matrix}{P_{1} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + I_{1} + T + ɛ_{P_{1}}}} & (1) \\{L_{1} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} - I_{1} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + ɛ_{L_{1}}}} & (2) \\{P_{2} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + I_{2} + T + ɛ_{P_{2}}}} & (15) \\{L_{2} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} - I_{2} + T + {\lambda_{2} \cdot N_{2}} + {\frac{c}{f_{2}}W} + ɛ_{L_{2}}}} & (16) \\{P_{3} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + I_{3} + T + ɛ_{P_{3}}}} & (23) \\{L_{3} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} - I_{3} + T + {\lambda_{3} \cdot N_{3}} + {\frac{c}{f_{3}}W} + ɛ_{L_{3}}}} & (24)\end{matrix}$

The definition of the parameters is as described above, and thus will nolonger be described.

At step S2110, the processing module may correct the above-describedobservation equations using only the partition comprehensive correctionx₄ and the correction parameters including at least one of the orbitcorrections x₁, the clock difference correction x₂ and the ionospherecorrection x₃. For example, in this embodiment, the above-describeobservation equations are corrected using only the partitioncomprehensive correction x₄, the clock difference correction x₂ and theionosphere correction x₃.

For example, the established pseudorange observation equations P₁(equation (1)), P₂ (equation (15)) and P₃ (equation (23)) andcarrier-phase observation equations L₁ (equation (2)), L₂ (equation(16)) and L₃ (equation (24)) are corrected by using the partitioncomprehensive correction x₄, the clock difference correction x₂ and theionosphere correction x₃ in the correction parameters, so that thecorrected pseudorange observation equation P₁(x) (equation (17)) andcarrier-phase observation equation L₁(x) (equation (18)) of the firstfrequency f₁, the corrected pseudorange observation equation P₂(x)(equation (19)) and carrier-phase observation equation L₂(x) (equation(20)) of the second frequency f₂, and the corrected pseudorangeobservation equation P₃(x) (equation (27)) and carrier-phase observationequation L₃(x) (equation (28)) of the second frequency f₃ may beobtained:

$\begin{matrix}{{P_{1}\left( {x_{2},x_{3},x_{4}} \right)} = {\rho + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} + {I_{1}\left( x_{3} \right)} + T + x_{4} + ɛ_{P_{1}}^{\prime}}} & (17) \\{{L_{1}\left( {x_{2},x_{3},x_{4}} \right)} = {\rho + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} - {I_{1}\left( x_{3} \right)} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + x_{4} + ɛ_{L_{1}}^{\prime}}} & (18) \\{{P_{2}\left( {x_{2},x_{3},x_{4}} \right)} = {\rho + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} + {I_{2}\left( x_{3} \right)} + T + x_{4} + ɛ_{P_{2}}^{\prime}}} & (19) \\{{L_{2}\left( {x_{2},x_{3},x_{4}} \right)} = {\rho + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} - {I_{2}\left( x_{3} \right)} + T + {\lambda_{2} \cdot N_{2}} + {\frac{c}{f_{2}}W} + x_{4} + ɛ_{L_{2}}^{\prime}}} & (20) \\{{P_{3}\left( {x_{2},x_{3},x_{4}} \right)} = {\rho + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} + {I_{3}\left( x_{3} \right)} + T + x_{4} + ɛ_{P_{3}}^{\prime}}} & (27) \\{{L_{3}\left( {x_{2},x_{3},x_{4}} \right)} = {\rho + {{c \cdot \delta}\; t} - {c \cdot \left( {{\delta\; t^{s}} - x_{2}} \right)} - {I_{3}\left( x_{3} \right)} + T + {\lambda_{3} \cdot N_{3}} + {\frac{c}{f_{3}}W} + x_{4} + ɛ_{L_{3}}^{\prime}}} & (28)\end{matrix}$

At step S2120, the above carrier-phase observations L₁(x₂−x₄)−L₃(x₂−x₄)corrected by the correction parameters are combined to construct acarrier-phase ionosphere-free combination, that is, a first observation(equation (31)):(αL ₁(x ₂ ,x ₃ ,x ₄)+βL ₂(x ₂ ,x ₃ ,x ₄)+γL ₃(x ₂ ,x ₃ ,x₄))/F(α,β,γ)  (31)

α,β, γ are the corresponding coefficients of three frequencyobservations respectively, F(α,β, γ) are the combination ofcoefficients, the selection of α,β, γ and F(α,β, γ) are applicable to acombination commonly used by a tri-frequency receiver currently, and theionosphere is eliminated by the above combination.

At step S2130, the above corrected/enhanced pseudorange observationsP₁(x₂−x₄)−P₃(x₂−x₄) are combined to construct a pseudorangeionosphere-free combination, that is, a second observation (equation(32)):(αP ₁(x ₂ ,x ₃ ,x ₄)+βP ₂(x ₂ ,x ₃ ,x ₄)+γP ₃(x ₂ ,x ₃ ,x₄))/F(α,β,γ)  (32)

α,β, γ are the corresponding coefficients of three frequencyobservations respectively, F(α,β, γ) are the combination ofcoefficients, the selection of α,β, γ and F(α,β, γ) are applicable to acombination commonly used by a tri-frequency receiver currently, and theionosphere is eliminated by the above combination.

At step S2140, the first observation and the second observation of eachof the N satellites are jointly solved by a solution procedure similarto the above, to obtain the operation result of the user positioning,where N is greater than 4. It should be noted that, in the procedure ofjoint solution, the weighting ratios of the observations are configuredby the above weight determination formula similar to that in step S1440,so that it can be obtained that the range of the weighting ratio is from1:0.01 to 1:0.05, with the optimal weighting ratio being preferred as1:0.01.

In addition to the above implementations, embodiments of the presentapplication may also receive and use only the partition comprehensivecorrection x₄ to correct the observation equations. In the following,description will be made by implementations of the single-frequency,dual-frequency and tri-frequency receivers using the partitioncomprehensive correction x₄.

FIG. 22 shows a flowchart of a navigation and positioning method of asingle-frequency receiver using correction parameters including apartition comprehensive correction x₄ according to an embodiment of thepresent application.

Referring to FIG. 22, at step S2200, the processing module receives thebasic broadcast messages and the partition comprehensive corrections x₄of N satellites. Based on the broadcast ephemeris, the pseudorangeobservation equation P₁ and the carrier-phase observation equation L₁ ofa single frequency of each satellite may be written, as above, as:

$\begin{matrix}{P_{1} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + I_{1} + T + ɛ_{P_{1}}}} & (1) \\{L_{1} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} - I_{1} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + ɛ_{L_{1}}}} & (2)\end{matrix}$

The definition of the parameters is as described above, and thus will nolonger be described.

At step S2210, the established pseudorange observation equation(equation (1)) and carrier-phase observation equation (equation (2)) arecorrected by using the correction parameters including the partitioncomprehensive correction x₄, so that the pseudorange observationequation P₁(x) (equation (34)) and the carrier-phase observationequation L₁(x) (equation (33)) corrected by the correction parametersmay be obtained:

$\begin{matrix}{{L_{1}\left( x_{4} \right)} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + x_{4} + ɛ_{L_{1}}^{\prime}}} & (33) \\{{P_{1}\left( x_{4} \right)} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + T + x_{4} + ɛ_{P_{1}}^{\prime}}} & (34)\end{matrix}$

wherein, ε_(L) ₁ ′ and ε_(P1)′ are the parameter-corrected observationnoises after combing pseudorange and carrier-phase, and the definitionof other parameters is as described above, and thus will no longer bedescribed. The partition comprehensive correction may also be at leastone or both of the GPS partition comprehensive correction and the Beidoupartition comprehensive correction. Here, the Beidou partitioncomprehensive correction is taken as an example.

At step S2220, by combining the above pseudorange observation equationP₁(x) and carrier-phase observation equation L₁(x) corrected, i.e., inequations (33), (34), it can constitute a combination that eliminatesthe influence of the ionosphere, that is, an ionosphere-free combinedobservation, as a first observation (the following equation (35)):

$\begin{matrix}{\frac{{L_{1}\left( x_{4} \right)} + {P_{1}\left( x_{4} \right)}}{2} = {\rho + {{c \cdot \delta}\; t} - {c\;\delta\; t^{s}} + T + {\quad{\frac{\lambda_{1} \cdot N_{1}}{2} + {\frac{c}{2f_{1}}W} + x_{4} + \frac{ɛ_{L_{1}}^{\prime} + ɛ_{P_{1}}^{\prime}}{2}}}}} & (35)\end{matrix}$

At step S2230, the corrected pseudorange observation equation P₁(x),that is, the above equation (34), is taken as a second observation.

At step S2240, the first observation (equation (35)) and the secondobservation (equation (34)) of each of the N satellites are jointlysolved to obtain the operation result of the user positioning, where Nis greater than 4. Specifically, the above equations (35) and (34) arecombined to form the observation equation of the navigation andpositioning of the single-frequency receiver. The correspondingobservation equation is as follows:

$\begin{bmatrix}{\frac{{L_{1}\left( x_{4} \right)} + {P_{1}\left( x_{4} \right)}}{2} - \rho_{1} - D_{\frac{L_{1} + P_{1}}{2}}} \\{{P_{1}\left( x_{4} \right)} - \rho_{1} - D_{P_{1}}} \\\vdots \\{\frac{{L_{n}\left( x_{4} \right)} + {P_{n}\left( x_{4} \right)}}{2} - \rho_{n} - D_{\frac{L_{n} + P_{n}}{2}}} \\{{P_{n}\left( x_{4} \right)} - \rho_{n} - D_{P_{n}}}\end{bmatrix} = {\quad{{{\left\lbrack \begin{matrix}\frac{X_{0} - X^{1}}{\rho} & \frac{Y_{0} - Y^{1}}{\rho} & \frac{Z_{0} - Z^{1}}{\rho} & 1 & M_{wet}^{1} & 0 & \cdots & 0 \\\frac{X_{0} - X^{1}}{\rho} & \frac{Y_{0} - Y^{1}}{\rho} & \frac{Z_{0} - Z^{1}}{\rho} & 1 & M_{wet}^{1} & 1 & \cdots & 0 \\\; & \; & \vdots & \; & \; & \; & \; & \; \\\frac{X_{0} - X^{n}}{\rho} & \frac{Y_{0} - Y^{n}}{\rho} & \frac{Z_{0} - Z^{n}}{\rho} & 1 & M_{wet}^{n} & 0 & \cdots & 0 \\\frac{X_{0} - X^{n}}{\rho} & \frac{Y_{0} - Y^{n}}{\rho} & \frac{Z_{0} - Z^{n}}{\rho} & 1 & M_{wet}^{n} & 0 & \cdots & 1\end{matrix} \right\rbrack\begin{bmatrix}{dX} \\{dY} \\{dZ} \\{{c \cdot \delta}\; t} \\{dZTD}_{W} \\B_{1} \\\vdots \\B_{n}\end{bmatrix}}\mspace{79mu}{wherein}\mspace{79mu} D_{\frac{L_{n} + P_{n}}{2}}} = {{{{- c}\;\delta\; t^{s}} + T + {\frac{c}{2f_{1}}W} + {x_{4}\mspace{79mu} D_{P}}} = {{{{- c} \cdot \delta}\; t} + T + x_{4}}}}}$

In the equation, [X₀, Y₀, Z₀] is the approximate coordinate of theobservation station; [X¹, Y¹, Z¹ ⋅ ⋅ ⋅ X^(n), Y^(n), Z^(n)] is thecoordinate of a satellite; [dX, dY, dZ] is the coordinate correctionparameters of the observation station; M_(wet) is the troposphere wetdelay mapping function; dZTD_(W) is the troposphere wet zenith delaycorrection parameters; w is the carrier-phase winding correction; B isthe carrier-phase ambiguity parameter in units of distance. According tothe above observation equation, those skilled in the art can solve thefinal operation result of the user positioning.

In addition, because the accuracies of different observation equationsare not uniform, it is necessary to perform weight determination on theobservation equations (that is, configure the corresponding weightingratios for the observations) and establish a stochastic model thereof.The observation equation noise is mainly composed of the errors ofrespective models:σ²=σ_(eph) ²+σ_(clk) ²+σ_(ion) ²+σ_(trop) ²+σ_(mp) ²+σ_(noise) ²

In the above equation, σ is the observation equation noise, and σ_(eph),σ_(clk), σ_(ion), σ_(trop), σ_(mp), σ_(noise) indicate the satelliteorbit accuracy, the satellite clock difference accuracy, the ionospheremodel accuracy, the troposphere model accuracy, the multipath modelaccuracy, and the observation noise accuracy respectively. Further, inorder to simplify the models, the above observation equation can bedivided into components (σ_(eph),σ_(clk)) that are independent of theelevation angle, and other parts are classified as components related tothe elevation angle (σ²(ele)), as follows:σ²=σ_(eph)+σ_(clk) ²+σ²(ele)

In the above equation, the weight of σ²(ele) is generally determinedaccording to the elevation angle:

$\quad\left\{ \begin{matrix}{{{\sigma({ele})} = \sigma_{0}},{{ele} > {30{^\circ}}}} \\{{{\sigma({ele})} = \frac{\sigma_{0}}{2{\sin({ele})}}},{{ele} \leq {30{^\circ}}}}\end{matrix} \right.$

Therefore, the stochastic model is as follows:

$Q = {R^{- 1} = \begin{bmatrix}\frac{1}{\sigma_{1}^{2}} & \; & \; \\\; & \ddots & \; \\\; & \; & \frac{1}{\sigma_{n}^{2}}\end{bmatrix}}$

In the above equation, Q is the weight matrix of the observation, R isthe covariance matrix of the observation. Through the solution of theabove-mentioned weight matrix of the observation, it can be obtainedthat the empirical weighting ratio here is optimally preferred as 1:0.05and that the amplitude range of the weighting ratio is from 1:0.01 to1:0.05.

FIG. 23 shows a flowchart of a navigation and positioning method of adual-frequency receiver using correction parameters including apartition comprehensive correction x₄ according to another embodiment ofthe present application.

At step S2300, since it is a dual-frequency receiver, the processingmodule here, in addition to receiving parameters and establishing thepseudo-range observation equation P₁ (equation (1)) and thecarrier-phase observation equation L₁ (equation (2)) of the firstfrequency f₁ as described above with reference to FIG. 22:

$\begin{matrix}{P_{1} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + I_{1} + T + ɛ_{P_{1}}}} & (1) \\{L_{1} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} - I_{1} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + ɛ_{L_{1}}}} & (2)\end{matrix}$further introduces a pseudo-range observation P₂ (equation (15)) and acarrier-phase observation L₂ (equation (16)) of a second frequency f₂other than the first frequency f₁:

$\begin{matrix}{P_{2} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + I_{2} + T + ɛ_{P_{2}}}} & (15) \\{L_{2} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} - I_{2} + T + {\lambda_{2} \cdot N_{2}} + {\frac{c}{f_{2}}W} + ɛ_{L_{2}}}} & (16)\end{matrix}$

The definition of the parameters is as described above, and thus will nolonger be described.

The meanings of the variables in the above equations (15) and (16) arethe same as those in the equations (1) and (2), except only that thesecond frequency f₂ is different from the first frequency f₁.

At step S2310, the established pseudorange observation equations(equation (1) and equation (15)) and carrier-phase observation equations(equations (2) and (16)) are corrected by using the correctionparameters (the correction parameters include the partitioncomprehensive correction x₄), so that the corrected pseudorangeobservation equation P₁(x) (equation (34)) and carrier-phase observationequation L₁(x) (equation (33)) of the first frequency f₁ and thecorrected pseudorange observation equation P₂(x) (equation (36)) andcarrier-phase observation equation L₂(x) (equation (37)) of the secondfrequency f₂ may be obtained:

$\begin{matrix}{{P_{1}\left( x_{4} \right)} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + T + x_{4} + ɛ_{P_{1}}^{\prime}}} & (34) \\{{L_{1}\left( x_{4} \right)} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + x_{4} + ɛ_{L_{1}}^{\prime}}} & (33) \\{{P_{2}\left( x_{4} \right)} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + T + x_{4} + ɛ_{P_{2}}^{\prime}}} & (36) \\{{L_{2}\left( x_{4} \right)} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + T + {\lambda_{2} \cdot N_{2}} + {\frac{c}{f_{2}}W} + x_{4} + ɛ_{L_{2}}^{\prime}}} & (37)\end{matrix}$

The meanings of the variables in the above equations (36) and (37) arethe same as those in the equations (34) and (33).

At step S2320, the carrier-phase observation equation L₁(x) and thecarrier-phase observation equation L₂(x) of the above equations (33) and(37) are combined to construct a carrier-phase ionosphere-freecombination, that is, a first observation:

$\begin{matrix}{L_{IF} = \frac{{f_{1}^{2}{L_{1}\left( x_{4} \right)}} - {f_{2}^{2}{L_{2}\left( x_{4} \right)}}}{f_{1}^{2} - f_{2}^{2}}} & (38)\end{matrix}$

At step S2330, the pseudorange observation equation P₁(x) and thepseudorange observation equation P₂(x) of the above equations (34) and(36) are combined to construct a pseudorange ionosphere-freecombination, that is, a second observation:

$\begin{matrix}{P_{IF} = \frac{{f_{1}^{2}{P_{1}\left( x_{4} \right)}} - {f_{2}^{2}{P_{2}\left( x_{4} \right)}}}{f_{1}^{2} - f_{2}^{2}}} & (39)\end{matrix}$

At step S2340, the first observation (equation (38)) and the secondobservation (equation (39)) of each of the N satellites are jointlysolved to obtain the operation result of the user positioning, where Nis greater than 4. It should be noted that, in the procedure of jointsolution, the weighting ratios of the observations are configured by theabove weight determination formula similar to that in step S2240, sothat it can be obtained that the weighting ratio is optimally preferredas 1:0.01, and the amplitude range of the weighting ratio is from 1:0.01to 1:0.05.

Refer to FIG. 24, which shows a flowchart of a navigation andpositioning method of a tri-frequency receiver using correctionparameters including a partition comprehensive correction x₄ accordingto another embodiment of the present application.

At step S2400, the processing module here receives the observationparameters corresponding to three frequencies f₁, f₂, f₃ respectively,and the processing module can select any two frequencies thereof (forexample, the processing module can select frequencies f₁ and f₂, orselect frequencies f₁ and f₃, or select frequencies f₂ and f₃) andestablish pseudorange observation equations and carrier-phaseobservation equations for the selected two frequencies.

For example, assuming that the frequencies selected by the processingmodule are f₁ and f₂, a pseudorange observation equation P₁ and acarrier-phase observation equation L₁ corresponding to the firstfrequency f₁ and a pseudo observation equation P₂ and a carrier-phaseobservation equation L₂ corresponding to the second frequency f₂ arerespectively established for the two frequencies:

$\begin{matrix}{P_{1}\; = \;{\rho\; + \;{{c \cdot \delta}\; t}\; - \;{{c \cdot \delta}\; t^{s}}\; + \; I_{1}\; + \; T + \; ɛ_{P_{1}}}} & (1) \\{L_{1}\; = \;{\rho\; + \;{{c \cdot \delta}\; t}\; - \;{{c \cdot \delta}\; t^{s}}\; - \; I_{1}\; + \; T\; + \;{\lambda_{1} \cdot N_{1}}\; + \;{\frac{c}{f_{1}}\; W}\; + \; ɛ_{L_{1}}}} & (2) \\{P_{2}\; = \;{\rho\; + \;{{c \cdot \delta}\; t}\; - \;{{c \cdot \delta}\; t^{s}}\; + \; I_{2}\; + \; T + \; ɛ_{P_{2}}}} & (15) \\{L_{2}\; = \;{\rho\; + \;{{c \cdot \delta}\; t}\; - \;{{c \cdot \delta}\; t^{s}}\; - \; I_{2}\; + \; T\; + \;{\lambda_{2} \cdot N_{2}}\; + \;{\frac{c}{f_{2}}\; W}\; + \; ɛ_{L_{2}}}} & (16)\end{matrix}$

The definition of the parameters is as described above, and thus will nolonger be described.

The meanings of the variables in the above equations (15) and (16) arethe same as those in the equations (1) and (2), except only that thesecond frequency f₂ is different from the first frequency f₁.

At step S2410, the established pseudorange observation equations(equation (1) and equation (15)) and carrier-phase observation equations(equations (2) and (16)) are corrected by using the correctionparameters (including the partition comprehensive correction x₄), sothat the corrected pseudorange observation equation P₁(x) (equation(34)) and carrier-phase observation equation L₁(x) (equation (33)) ofthe first frequency f₁ and the corrected pseudorange observationequation P₂(x) (equation (36)) and carrier-phase observation equationL₂(x) (equation (37)) of the second frequency f₂ may be obtained:

$\begin{matrix}{{P_{1}\left( x_{4} \right)} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + T + x_{4} + ɛ_{P_{1}}^{\prime}}} & (34) \\{{L_{1}\left( x_{4} \right)} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + x_{4} + ɛ_{L_{1}}^{\prime}}} & (33) \\{{P_{2}\left( x_{4} \right)} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + T + x_{4} + ɛ_{P_{2}}^{\prime}}} & (36) \\{{L_{2}\left( x_{4} \right)} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + T + {\lambda_{2} \cdot N_{2}} + {\frac{c}{f_{2}}W} + x_{4} + ɛ_{L_{2}}^{\prime}}} & (37)\end{matrix}$

The meanings of the variables in the above equations (36) and (37) arethe same as those in the equations (34) and (33).

At step S2420, the carrier-phase observation equation L₁(x) and thecarrier-phase observation equation L₂(x) of the above equations (33) and(37) are combined to construct a carrier-phase ionosphere-freecombination, that is, a first observation:

$\begin{matrix}{L_{IF} = \frac{{f_{1}^{2}{L_{1}\left( x_{4} \right)}} - {f_{2}^{2}{L_{2}\left( x_{4} \right)}}}{f_{1}^{2} - f_{2}^{2}}} & (38)\end{matrix}$

At step S2430, the pseudorange observation equation P₁(x) and thepseudorange observation equation P₂(x) of the above equations (34) and(36) are combined to construct a pseudorange ionosphere-freecombination, that is, a second observation:

$\begin{matrix}{P_{IF} = \frac{{f_{1}^{2}{P_{1}\left( x_{4} \right)}} - {f_{2}^{2}{P_{2}\left( x_{4} \right)}}}{f_{1}^{2} - f_{2}^{2}}} & (39)\end{matrix}$

At step S2440, the first observation (equation (38)) and the secondobservation (equation (39)) of each of the N satellites are jointlysolved to obtain the operation result of the user positioning, where Nis greater than 4. It should be noted that, in the procedure of jointsolution, the weighting ratios of the observations are configured by theabove weight determination formula similar to that in step S2240, sothat it can be obtained that the weighting ratio is optimally preferredas 1:0.01, and the amplitude range of the weighting ratio is from 1:0.01to 1:0.05.

In addition, the navigation and positioning method using tri-frequencyis not limited to the above implementation of selecting two frequenciesthereof; instead, a method of simultaneously using three frequencies toperform navigation and positioning operation can be realized.

For example, FIG. 25 shows a flowchart of another navigation andpositioning method of a tri-frequency receiver using correctionparameters (the correction parameters include a partition comprehensivecorrection x₄) according to an embodiment of the present application.

Referring to FIG. 25, at step S2500, since it is a tri-frequencyreceiver, the processing module here receives observation parameterscorresponding to three frequencies f₁, f₂, f₃ respectively, and theprocessing module respectively establishes three pseudorangeobservations P₁ (equation (1)), P₂ (equation (15)), P₃ (equation (23))and three carrier-phase observations L₁ (equation (2)), L₂ (equation(16)), L₃ (equation (24)) corresponding to f₁, f₂ and f₃:

$\begin{matrix}{P_{1}\; = \;{\rho\; + \;{{c \cdot \delta}\; t}\; - \;{{c \cdot \delta}\; t^{s}}\; + \; I_{1}\; + \; T + \; ɛ_{P_{1}}}} & (1) \\{L_{1}\; = \;{\rho\; + \;{{c \cdot \delta}\; t}\; - \;{{c \cdot \delta}\; t^{s}}\; - \; I_{1}\; + \; T\; + \;{\lambda_{1} \cdot N_{1}}\; + \;{\frac{c}{f_{1}}\; W}\; + \; ɛ_{L_{1}}}} & (2) \\{P_{2}\; = \;{\rho\; + \;{{c \cdot \delta}\; t}\; - \;{{c \cdot \delta}\; t^{s}}\; + \; I_{2}\; + \; T + \; ɛ_{P_{2}}}} & (15) \\{L_{2}\; = \;{\rho\; + \;{{c \cdot \delta}\; t}\; - \;{{c \cdot \delta}\; t^{s}}\; - \; I_{2}\; + \; T\; + \;{\lambda_{2} \cdot N_{2}}\; + \;{\frac{c}{f_{2}}\; W}\; + \; ɛ_{L_{2}}}} & (16) \\{P_{3} = {\rho\; + \;{{c \cdot \delta}\; t}\; - \;{{c \cdot \delta}\; t^{s}}\; + \; I_{3}\; + \; T + \; ɛ_{P_{3}}}} & (23) \\{L_{3}\; = \;{\rho\; + \;{{c \cdot \delta}\; t}\; - \;{{c \cdot \delta}\; t^{s}}\; - \; I_{3}\; + \; T\; + \;{\lambda_{3} \cdot N_{3}}\; + \;{\frac{c}{f_{3}}\; W}\; + \; ɛ_{L_{3}}}} & (24)\end{matrix}$

The definition of the parameters is as described above, and thus will nolonger be described.

At step S2110, the established three groups of pseudorange observationequations (equation (1), equation (15) and equation (23)) andcarrier-phase observation equations (equation (2), equation (16) andequation (24)) are corrected by using the correction parameters (thecorrection parameters include the partition comprehensive correctionx₄), so that the corrected pseudorange observation equation P₁(x)(equation (34)) and carrier-phase observation equation L₁(x) (equation(33)) of the first frequency f₁, the corrected pseudorange observationequation P₂(x) (equation (36)) and carrier-phase observation equationL₂(x) (equation (37)) of the second frequency f₂, and the correctedpseudorange observation equation P₃(x) (equation (40)) and carrier-phaseobservation equation L₃(x) (equation (41)) of the second frequency f₃may be obtained:

$\begin{matrix}{{P_{1}\left( x_{4} \right)} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + T + x_{4} + ɛ_{P_{1}}^{\prime}}} & (34) \\{{L_{1}\left( x_{4} \right)} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + T + {\lambda_{1} \cdot N_{1}} + {\frac{c}{f_{1}}W} + x_{4} + ɛ_{L_{1}}^{\prime}}} & (33) \\{{P_{2}\left( x_{4} \right)} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + T + x_{4} + ɛ_{P_{2}}^{\prime}}} & (36) \\{{L_{2}\left( x_{4} \right)} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + T + {\lambda_{2} \cdot N_{2}} + {\frac{c}{f_{2}}W} + x_{4} + ɛ_{L_{2}}^{\prime}}} & (37) \\{{P_{3}\left( x_{4} \right)} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + T + x_{4} + ɛ_{P_{3}}^{\prime}}} & (40) \\{{L_{3}\left( x_{4} \right)} = {\rho + {{c \cdot \delta}\; t} - {{c \cdot \delta}\; t^{s}} + T + {\lambda_{3} \cdot N_{3}} + {\frac{c}{f_{3}}W} + x_{4} + ɛ_{L_{3}}^{\prime}}} & (41)\end{matrix}$

At step S2520, the above carrier-phase observation equationsL₁(x₄)−L₃(x₄) corrected by the correction parameters are combined toconstruct a carrier-phase ionosphere-free combination, that is, a firstobservation (equation (42)):(αL ₁(x ₄)+βL ₂(x ₄)+γL ₃(x ₄))/F(α,β,γ)  (42)

α,β, γ are the corresponding coefficients of three frequencyobservations respectively, F(α,β, γ) are the combination ofcoefficients, the selection of α,β, γ and F(α,β, γ) are applicable to acombination commonly used by tri-frequency currently, and the ionosphereis eliminated by the above combination.

At step S2530, the above pseudorange observation equations P₁(x₄)−P₃(x₄)corrected by the correction parameters are combined to construct apseudorange ionosphere-free combination, that is, a second observation(equation (43)):(αP ₁(x ₄)+βP ₂(x ₄)+γP ₃(x ₄))/F(α,β,γ)  (43)

α,β, γ are the corresponding coefficients of three frequencyobservations respectively, F(α,β, γ) are the combination ofcoefficients, the selection of α,β, γ and F(α,β, γ) are applicable to acombination commonly used by tri-frequency currently, and the ionosphereis eliminated by the above combination.

At step S2540, the first observation and the second observation of eachof the N satellites are jointly solved by a solution procedure similarto the above, to obtain the operation result of the user positioning,where N is greater than 4. It should be noted that, in the procedure ofjoint solution, the weighting ratios of the observations are configuredby the above weight determination formula similar to that in step S2240,so that it can be obtained that the range of the weighting ratio is from1:0.01 to 1:0.05, with the optimal weighting ratio being preferred as1:0.01.

Embodiments of the present invention have at least one of the followingbeneficial effects:

The embodiments of the invention improve the accuracy of positioning(achieve at least the decimeter-level accuracy of positioning) throughthe superimposition of the correction parameters (protocolsuperimposition) and the cooperation of the updating of the correctionparameters with the protocol superposition, thereby meeting therequirements of high-accuracy positioning of different industriesincluding, but not limited to, measurement, mechanical control,precision agriculture, intelligent transportation, logistics and assettracking, engineering management, engineering construction, navigationfor the blind, early warning monitoring, emergency rescue, etc.Furthermore, the embodiments of the present invention further reduce thehardware complexity of the user end and can also realize real-timehigh-accuracy navigation and positioning, and/or the embodiments of theinvention further improve the convergence speed and achieve fastconvergence, thereby shortening the initialization time of the receiver,so that the receiver is quickly brought into a substantial high-accuracypositioning working state.

It should be noted that, in this specification, the terms “include”,“comprise” or any other variations thereof are intended to covernon-exclusive inclusions so that a procedure, method, article or devicethat includes a series of elements includes not only those elements, butalso includes other elements that are not explicitly listed, or elementsthat are inherent to such a procedure, method, article or device. Withno more limitation, the element defined by the sentence “include one . .. ” does not exclude that there is another same element in theprocedure, method, article, or device including the element.

Finally, it should also be noted that the above-described series ofprocesses includes not only processes performed chronologically in theorder described herein but also processes performed in parallel orindividually rather than chronologically.

With the above description of the embodiments, those skilled in the artcan clearly understand that the present invention can be implemented bymeans of software plus a necessary hardware platform, and of course canalso be implemented entirely by hardware. Based on such understanding,all or part of the contribution of the technical scheme of the presentinvention to the background can be embodied in the form of a softwareproduct which can be stored in a storage medium such as a ROM/RAM, amagnetic disk, an optical disk, etc. and includes several instructionsfor causing a computer device (which may be a personal computer, aserver, or a network device, etc.) to perform the methods described invarious embodiments of the present invention or certain portions of theembodiments.

In embodiments of the present invention, units/modules may beimplemented in software for execution by various types of processors.For example, an identified executable code module may include one ormore physical or logical blocks of computer instructions, which may beconstructed as objects, procedures, or functions, for example.Nevertheless, the executable codes of the identified modules need not bephysically located together, but may include different instructionsstored in different bits. When these instructions are logically combinedtogether, they constitute a unit/module and implement the specifiedpurpose of the unit/module.

When the unit/module can be implemented by means of software, takinginto account the level of the existing hardware process, for theunit/module can be implemented in software, the corresponding hardwarecircuit can be built by those skilled in the art to achieve thecorresponding function without considering the cost, the hardwarecircuit including conventional Very Large Scale Integration (VLSI)circuits or gate arrays and existing semiconductors such as logic chips,transistors or the like, or other discrete components. The module canalso be implemented with programmable hardware devices such as fieldprogrammable gate arrays, programmable array logic, programmable logicdevices, and the like.

The present invention has been described in detail above, and theprinciples and implementations of the present invention are elaboratedusing specific examples herein. The above explanation of embodiments isonly used for helping to understand the methods of the present inventionand the core ideas thereof; meanwhile, for the ordinary skill in theart, in light of the ideas of the present invention, there will bechanges in specific implementations and application scopes. In summary,the contents of this specification should not be construed as thelimiting of the present invention.

What is claimed is:
 1. A method for navigation and positioning of areceiver, the method comprising: receiving basic broadcast messages andcorrection parameters of a plurality of satellites, and establishing apseudorange observation equation and a phase observation equationcorresponding to each of the plurality of satellites respectively basedon the received basic broadcast messages; correcting the pseudorangeobservation equation and the phase observation equation using thereceived correction parameters corresponding to each of the plurality ofsatellites to obtain the corrected pseudorange observation equation andthe corrected phase observation equation; constructing anionosphere-free combined observation of each of the plurality ofsatellites as a first observation for a single-frequency receiveraccording to the corrected pseudorange observation equation and thecorrected phase observation equation, and constructing anionosphere-free combined observation of each of the plurality ofsatellites as a first observation for a dual-frequency receiver or atri-frequency receiver according to the corrected phase observationequation; constructing a second observation corresponding to each of theplurality of satellites according to the corrected pseudorangeobservation equation; and jointly solving the first observations and thesecond observations of the plurality of satellites to obtain anoperation result of user positioning, wherein the correction parametersis are selected from the following combinations: a partitioncomprehensive correction number x₄; and a combination of the partitioncomprehensive correction number x₄ and at least one of an orbitcorrection number x₁, a clock difference correction number x₂ and anionosphere correction number x₃.
 2. A receiver, comprising: an antennafor receiving basic broadcast messages and correction parameters; atleast one storage apparatus for storing the basic broadcast messages andthe correction parameters received; a processing module for processingthe basic broadcast messages and correction parameters in the storageapparatus to obtain an operation result of user positioning; and a userinteraction module for indicating the operation result of the userpositioning, wherein the processing module is used to perform thefollowing operations: receiving basic broadcast messages and correctionparameters of a plurality of satellites, and establishing a pseudorangeobservation equation and a phase observation equation corresponding toeach of the plurality of satellites respectively based on the receivedbasic broadcast messages; correcting the pseudorange observationequation and the phase observation equation using the receivedcorrection parameters corresponding to each of the plurality ofsatellites to obtain the corrected pseudorange observation equation andthe corrected phase observation equation; constructing anionosphere-free combined observation of each of the plurality ofsatellites as a first observation for a single-frequency receiveraccording to the corrected pseudorange observation equation and thecorrected phase observation equation, and constructing anionosphere-free combined observation of each of the plurality ofsatellites as a first observation for a dual-frequency receiver or atri-frequency receiver according to the corrected phase observationequation; constructing a second observation corresponding to each of theplurality of satellites according to the corrected pseudorangeobservation equation; and jointly solving the first observations and thesecond observations of the plurality of satellites to obtain theoperation result of the user positioning, wherein the correctionparameters is are selected from the following combinations: a partitioncomprehensive correction number x₄; and a combination of the partitioncomprehensive correction number x₄ and at least one of an orbitcorrection number x₁, a clock difference correction number x₂ and anionosphere correction number x₃.
 3. The receiver according to claim 2,wherein the receiver is one of single-frequency receiver, adual-frequency receiver or a tri-frequency receiver.
 4. The receiveraccording to claim 3, wherein for the single-frequency receiver, thefirst observation is (P₁ (x)+L₁ (x))/2, where P₁(x) is the pseudorangeobservation equation corrected by the correction parameters and L₁(x) isthe phase observation equation corrected by the correction parameters.5. The receiver according to claim 3, wherein for the single-frequencyreceiver, the second observation is P₁ (x).
 6. The receiver according toclaim 3, wherein for a dual-frequency receiver, the first observation isthe ionosphere-free combined observation: (f₁ ²L₁ (x)-f₂ ²L₂(x))/(f₁²-f₂ ²), where L₁(x) and L₂(x) are the phase observation equationscorrected by the correction parameters, and f₁ is a first frequencywhile f₂ is a second frequency, the first frequency being different fromthe second frequency.
 7. The receiver according to claim 6, wherein forthe dual-frequency receiver, the second observation is (f₁ ²P₁(x)−f₂²P₂(x))/(f₁ ²f₂ ²) where P₁(x) and P₂(x) are the pseudorange observationequations corrected by the correction parameters, and f₁ is a firstfrequency while f₂ is a second frequency, the first frequency beingdifferent from the second frequency.
 8. The receiver according to claim3, wherein for a tri-frequency receiver, any two of three frequenciesf₁, f₂ and f₃ are selected, the first observation (f₁ ²L₁(x)−f₂²L₂(x))/(f₁ ²f₂ ²) and the second observation (f₁ ²P₁(x)f₂ ²P₂(x))/(f₁²−f₂ ²) are established, where L₁(x) and L₂(x) are the phase observationequations corrected by the correction parameters and P₁ (x) and P₂(x)are the pseudorange observation equations corrected by the correctionparameters, and f₁ and f₂ represent any two frequencies of a firstfrequency, a second frequency and a third frequency, the firstfrequency, the second frequency and the third frequency being differentfrom each other.
 9. The receiver according to claim 8, wherein for thetri-frequency receiver, the three frequencies f₁, f₂ and f₃ to constructthe first observation as (αL₁(x)+βL₂(x)+γL₃(x))/F(α,β, γ) and toconstruct the second observation as (αP₁ (x)+βP₂(x)+γP₃(x))/F(α,β, γ),where L₁(x), L₂(x) and L₃(x) are the phase observation equationscorrected by the correction parameters and P₁(x), P₂(x) and P₃(x) arethe pseudorange observation equations corrected by the correctionparameters, and f₁ is a first frequency, f₂ is a second frequency and f₃is a third frequency, and α,β, γ are the corresponding coefficients ofobservations of the three frequencies respectively and F(α,β, γ) is acombination of the coefficients, and the first frequency, the secondfrequency and the third frequency are different from each other.
 10. Thereceiver according to claim 2, wherein the partition comprehensivecorrection number is at least one or both of a GPS partitioncomprehensive correction number and a Beidou partition comprehensivecorrection number.
 11. The receiver according to claim 3, wherein thepositioning of a user is solved jointly based on the first observationsand the second observation obtained by the plurality of satellites, andwherein the amplitude range of the weighting ratio of the firstobservations and the second observations is from 1:0.01 to 1:0.05. 12.The receiver according to claim 3, wherein the positioning of a user issolved jointly based on the first observations and the secondobservation obtained by the plurality of satellites, and wherein theweighting ratio of the first observations and the second observations is1:0.05.
 13. The receiver according to claim 6, wherein the positioningof a user is solved jointly based on the first observations and thesecond observation obtained by the plurality of satellites, and whereinthe weighting ratio of the first observations and the secondobservations is 1:0.01.
 14. The receiver according to claim 6, whereinthe positioning of a user is solved jointly based on the firstobservations and the second observation obtained by the plurality ofsatellites, and wherein the amplitude range of the weighting ratio ofthe first observations and the second observations is from 1:0.01 to1:0.05.
 15. The receiver according to claim 8, wherein the positioningof a user is solved jointly based on the first observations and thesecond observation obtained by the plurality of satellites, and whereinthe amplitude range of the weighting ratio of the first observations andthe second observations is from 1:0.01 to 1:0.05.
 16. The receiveraccording to claim 8, wherein the positioning of a user is solvedjointly based on the first observations and the second observationobtained by the plurality of satellites, and wherein the weighting ratioof the first observations and the second observations is 1:0.01.
 17. Thereceiver according to claim 9, wherein the positioning of a user issolved jointly based on the first observations and the secondobservation obtained by the plurality of satellites, and wherein theweighting ratio of the first observations and the second observations is1:0.01.
 18. A non-transitory computer readable medium comprisinginstructions which, when executed by at least one processing module,cause the at least one processing module to perform a method fornavigational and positioning, the method comprising: receiving basicbroadcast messages and correction parameters of a plurality ofsatellites, and establishing a pseudorange observation equation and aphase observation equation corresponding to each of the plurality ofsatellites respectively based on the received basic broadcast messages;correcting the pseudorange observation equation and the phaseobservation equation using the received correction parameterscorresponding to each of the plurality of satellites to obtain thecorrected pseudorange observation equation and the corrected phaseobservation equation; constructing an ionosphere-free combinedobservation of each of the plurality of satellites as a firstobservation for a single-frequency receiver according to the correctedpseudorange observation equation and the corrected phase observationequation, and constructing an ionosphere-free combined observation ofeach of the plurality of satellites as a first observation for adual-frequency receiver or a tri-frequency receiver according to thecorrected phase observation equation; constructing a second observationcorresponding to each of the plurality of satellites according to thecorrected pseudorange observation equation; and jointly solving thefirst observations and the second observations of the plurality ofsatellites to obtain an operation result of the user positioning,wherein the correction parameters are selected from the followingcombinations: a partition comprehensive correction number x₄; and acombination of the partition comprehensive correction number x₄ and atleast one of an orbit correction number x₁, a clock differencecorrection number X₂ and an ionosphere correction number x₃.